Nikki is an individualistic, rebellious tomboy of Chinese-Canadian background who wears ripped sleeveless shirts, dyes her naturally-black hair purple and sports a nose ring, a pierced left eyebrow and multiple piercings in both ears. She has a sarcastic personality, a quick wit and a sharp tongue and is quick to laugh at the humorous misfortunes of others, but she also cares about her friends and will stand up for them when needed, occasionally even making threats of physical violence against those foolish enough to hassle her pals.
For most of the series, Nikki works at the Khaki Barn as a sales associate, but she hates her job there because of her co-workers, three girls named Chrissy, Kirsten and Kristen (whom Nikki nicknamed "The Clones"), so she sets out to torment them by doing as little work as possible and slacking when she does work. She also once worked briefly at Stereo Shack under the watch of a Star Wars geek named Darth, who had an unrequited crush on Nikki. She is embarrassed by her parents because of their choice to wear dated outfits from the 1970s. She loves listening to rock music, but also secretly likes the boy band DawgToy (which Caitlin and Jen, who are also fans of the band, later discover to their delight and Nikki's embarassment). She was initially unfriendly toward Caitlin, although she later warmed up to her and welcomed her into the gang.
Nikki has an on-again, off-again romantic relationship with Jonesy, which has gone on since early in the series. They first got together when Jonesy dared her to see a movie with him so he could show her proof of a line that was said, which Nikki disputed, in that movie. Nikki and Jonesy later split up after a disastrous three-month anniversary celebration and Nikki moves on to dating another guy while Jonesy returns to his old womanizing ways, but they eventually come to realize how much they really mean to each other and they get back together. Despite Jonesy's annoying habits (and his tendency to frequently get fired from his jobs) and Nikki's sarcasm and outspokenness, their love for each other enables the couple to weather all that life throws their way and be stronger for it.
In 6teen's series finale, Nikki finds out that she has to move with her parents to Iqaluit, Nunavut due to her father getting a new job there. She is resistant to the idea and wants to remain in town with her friends (even going so far as to room with Jen at the Garcia/Masterson house over Mr. and Mrs. Wong's objections because of Jonesy living under the same roof), and the Wongs later appear to change their minds about moving so that Nikki can remain together with the gang, but Nikki, who realizes that her parents have made sacrifices for her over time, decides to do the same for them and agrees to move up north with them. As one of her final acts before moving, Nikki sticks it to The Clones by quitting the Khaki Barn for good, then at a going away party thrown for her by the gang at Grind Me, she promises to keep in touch with her friends. Afterward at the Big Squeeze, Nikki calls Jonesy from her Iqaluit-bound plane and promises to stay involved with him as the gang bids her farewell.
After being turned down for employment in a travel agency at The Galleria, Nikki lands her first job--but it turns out to be at the Khaki Barn, much to her chagrin ("Take This Job and Squeeze It"). She devises a plan to take the day off work to join her friends at the mall's indoor amusement park ("The Big Sickie"), and she befriends Caitlin, after her initial attitude of low-key hostility toward the peppy rich girl, and accepts her into the gang after Caitlin helps to convince a reluctant Jen to take the day off as well. Nikki competes with Jude over who will get one of two backstage passes Wyatt has obtained for a concert by rock band The Mighty Weasels ("A Lime to Party"), but Wyatt decides not to give either one the second pass after their competition gets out of hand. She temporarily assumes management of the Khaki Barn after assistant manager and head Clone Chrissy goes out ("The Sushi Connection"), and she gets revenge on Caitlin's behalf against Kyle Donaldson (a notorious womanizer who took Cait out on a disastrous date) by convincing Kyle to buy two pairs of too-small cargo pants. She gets set up on a date with geeky Star Wars fan and Stereo Shack employee Darth by Jonesy at Darth's request ("Breaking Up with the Boss' Son"), but Nikki does not return her nerdy suitor's affection.
Nikki falls victim to Chrissy's scheme to try to mold her into the ideal Khaki Barn employee through the use of reverse psychology by making her the store's employee of the month ("Employee of the Month"), but her friends snap her out of the brainwashing techniques used by the Khaki Barn and, after coming to her senses, she makes sure Chrissy knows she won't be controlled. She tries out for the American Idol-like Star Contest and purposely delivers a bad audition to give Wyatt a chance to win the local competition ("Idol Time at the Mall") and is one of the subjects of the song Wyatt performs to win the contest. She and Jonesy go on their first date, a trip to the movies ("The Fake Date"), and they literally get at each other's throats when they get stuck in an elevator together afterward. Although she publicly professes to hate boy bands, Nikki wins a competition to appear in a video for the boy band DawgToy, angering Jen (who had also auditioned and thought herself a shoo-in to win) in the process ("The Girls in the Band"), and Nikki's secret crush on DawgToy is later accidentally exposed, which she confesses to Jen and Caitlin before she invites both girls to join her for the band's show and the post-show backstage party.
Nikki and Jonesy start becoming more attracted to each other romantically, despite Caitlin, Jen and Wyatt's efforts to prevent it from happening, after she gets Jonesy a job at the Khaki Barn ("Clonesy"). She boycotts celebrating Valentine's Day due to past bad experiences with dates on that day ("Stupid Over Cupid") and she convinces Jen and Caitlin to join her for some dateless fun, then she saves Jonesy, who has set up a Valentine's Day date auction to try to score a date but sees his plan backfire when he gets less-than-welcome bids from some unexpected bidders, by placing a last-second bid which has a price on it for him. She comes down sick with food poisoning after eating tainted samples of a snack food called Roast Burkey Chunklets, which Jude unintentionally allowed to turn putrid when he forgets to plug in the freezer he puts them in after Jonesy entrusts him with their storage ("The Khaki Girl"). She helps Wyatt, who is afraid of heights, get down from the top of a tall ladder outside of Spin This by making him forget his fear ("The Swami"), doing so by criticizing his choice of favorite rock bands and getting him to argue with her about it as he neglects to notice he's climbing down the ladder. She beats Jude in a staring contest as part of a "Battle of the Sexes" when Jude forgets what he's doing and quickly blinks first ("Bring It On"), then she, Caitlin and Jen lend Jude, Jonesy and Wyatt a hand when the guys are forced to admit defeat after they get in over their heads looking after some bratty kids in the mall's daycare. She becomes the target of a prank planned and filmed by Jonesy for public access TV ("Cecil B. Delusioned") when his accomplice Caitlin, under the ruse of a breakup with a boyfriend, convinces her to get a fashion makeover, which does not go over well with Nikki when she finds out about the prank.
Nikki joins with the gang in throwing a makeshift 16th birthday party for Wyatt, who is wary of such parties due to past experience with his family throwing weirdly-themed parties for him, by covertly hijacking a bridal shower at Albatross & Finch after the gang's busy schedules keep them from planning a proper celebration for him until they're too late ("The Birthday Boy"). She undergoes an uncharacteristic change in personality, becoming more emotional and friendly and eating chocolate (which she normally hates) due to the effects of premenstrual syndrome ("Enter the Dragon"). She takes part in a bet the gang makes with Jen, in which they bet that Jen, who often gives out unsolicited opinions and advice to her friends, can't keep her opinions to herself for one day ("One Quiet Day"), and Nikki and the gang try to make Jen lose the bet by coming up with outrageous ideas like, in Nikki's case, getting a tattoo of a bulldog. She meets Jen's sister Courtney ("It's Always Courtney, Courtney, Courtney!"), who tells Nikki about her days as a Khaki Barn employee and gives her tips on how to change the system she works for from within as they strike up a bond. On a day off from school, Nikki spends the day trying to avoid seeing her parents, who are at the mall, with help from Jude ("The One with the Text Message") while she helps Wyatt deal with his being dumped by his girlfriend Serena via text message and she performs makeovers on dresses Caitlin and Jen have bought for a homecoming dance. She pranks The Clones for Halloween by fooling them into eating Halloween candy, telling them that a Halloween candy diet can help them lose weight ("Boo, Dude").
Nikki is shocked to learn that the results of a test she took for her school's career day have her future career listed as "Retail Specialist" ("Career Day"), then finds out that Jude accidentally mixed up Caitlin's test with her own, which actually gives her a future career as a travel writer. She and Caitlin fall out when they argue after Nikki has enough of Cait constantly talking about new boyfriend Wade ("Fish and Make Up"), but they make up after Jude's pet goldfish, Fish, dies suddenly. She and Jonesy stress over what to get each other for their three-month anniversary, which is not helped by their friends' gift suggestions as the rest of the gang report to each other and to Nikki and Jonesy about who is buying what ("Unhappy Anniversary"), and after the gang sets them up on a disastrous romantic date, Nikki tells Jonesy that the best thing to do, for the long-term sake of their friendship, is to end the romantic relationship for the time being. She makes the mistake of telling an embarassing secret (running head-first into a stop sign) to Caitlin, who then spreads Nikki and her friends' secrets to the rest of the mall through her boyfriend Dustin ("Pillow Talk"), so the gang gets revenge on Caitlin, who conveniently did not tell her own secret to Dustin, by getting help from Tricia to expose Cait's secret to her beau. After Caitlin gives up her Big Squeeze job when she finally pays off her credit card bill and the gang lose their table at the lemonade stand to a group of doppelgangers led by Tricia, Nikki teams up with her friends to stage an intervention on Caitlin to convince her to get her job back so they can take back their table ("Losing Your Lemon").
Nikki gets fired from the Khaki Barn after Chrissy finds out she had told Jonesy that Chrissy is a member of Darth's Star Wars Jedi Knight club, so she gets a new job under Darth at Stereo Shack ("Welcome to the Darth Side"), and after having to fend off Darth's advances, she gets Caitlin to help her set the geeky Star Wars disciple up with Julie, the skinny, awkward Wonder Taco employee, then she gets her job at the Khaki Barn back after The Clones convince her to return because a fourth Clone, Ashley, had been taking all their sales. She takes Ron the Rent-a-cop under her wing at the Khaki Barn after Ron quits his job as the Galleria head of security due to a prank by Jonesy and Jude ("The New Guy") and has fun watching as Ron puts his military experience to use to put The Clones in line. She contemplates not going on a trip with her parents to Mexico for Christmas ("In a Retail Wonderland..."), but Caitlin convinces her to do so after Nikki helps her get back her will to shop. She gets in touch with Jen via cell phone on her way back from Mexico to fill her in on her vacation, then returns in time to join the gang for New Year's Eve celebrations ("Midnight Madness").
Nikki makes the mistake of putting on a pair of rubber flip-flop sandals, under coercion from Kirsten (who claims that Chrissy gave her permission to fire Nikki if she did not), to wear for a flip-flop sale, and the sandals cause her feet to blister and bleed when she walks around all day in them ("Waiting to Ex-Sale"), while she teases Jonesy for being afraid to donate blood. She gets Caitlin to help her score a date with Albatross and Finch Greeter God Hunter, then falls out with Cait after finding out that Hunter went out with her instead ("The Hunted"), but the two girls make up again after they learn Hunter two-timed them both with other girls and they set out to teach him a lesson. She is falsely accused of theft from the Khaki Barn by The Clones and quits over the harassment, then gets hired back with bonus perks after she threatens to report The Clones to the KB head office when they find out Nikki is innocent all along ("The Wedding Destroyers"), and when Jonesy and his brothers begin feuding with Jen and Courtney over the pending wedding of their parents, Nikki recruits Ron to get the Garcia and Masterson offspring to resolve their differences in time for the nuptials. She meets and bonds with a new guy named Stone, who appears to be a match with Nikki personality-wise ("Jonesy's Low Mojo"), and when she and Stone go out on a date, Caitlin and Jen secretly follow along to make sure Nikki is okay.
Nikki gets roped into helping Caitlin pretend to be a college girl in order to impress a college media student named Josh ("Smarten Up"), and she and the rest of the gang later keep up the charade by pretending to be college students themselves so Cait can hang on to Josh. When she finds out that Stone had hired Jonesy to break up with her for him because he was too chicken to do it himself (only for Jonesy to refuse to do so), Nikki beats Stone to the punch by dumping him instead ("Dirty Work"), then forces Caitlin to give up a bronzing makeup that causes her face to break out in zits. She helps Caitlin try to clear her name and prove her innocence after Tricia frames Cait for shoplifting from Albatross & Finch ("A Crime of Fashion"), and with Darth joining in to help with some gadgets, they find the security tape they need and succeed in clearing Caitlin and getting Tricia arrested for shoplifting. She reluctantly agrees to run for school Spring Queen against Tricia so she can use the title as a platform for an environmental cause she supports ("Spring Fling"), and with the gang lending a hand in her campaign, she overcomes Tricia's attempts to steal their campaign ideas (which the snobby rich girl accomplishes by trying to seduce weak link Jonesy) and captures the Spring Queen crown. She and Jonesy get into a fight at the mall ice rink when Jonesy lets her fall to the ice after he gets distracted by another girl while teaching Nikki to ice skate, and both get arrested by Ron for it ("Snow Job"), then after she tells Jonesy why she first broke up with him after he finds her crying at the ice rink, the couple finally gets back together and head to the school winter dance, where the rest of the gang delight in seeing Nikki and Jonesy together again.
- Nikki is the only member of the gang whose name is the same in the French-dubbed version of the series as it is in the original English version
- In 6teen's pre-development incarnation as The Mall, Nikki sports shorter, red-dyed hair, her white tank top is shorter and more midriff-baring, her cargo pants have red patches on the pockets, and her skin has more of a pale-yellowish tint in reflection of her Asian background