Nelly is a female 4th grade student at South Park Elementary. She first appeared in the Season Nine episode, "Free Willzyx" and received her first speaking role in the Season Eleven episode, "The List".
In "The List", she was attacked by Butters in Operation Cannot Possibly Fail when he tried to kick her in the groin, which did nothing, due to Eric Cartman's ignorance of the female body. Nelly beats up Butters, giving him a black eye. Another attempt was made in Operation Cannot Possibly Fail A Second Time, during which the list was successfully taken from Nelly.
Nelly has brown hair and parts it into two pigtails. She wears a light green sweater with a picture of a daisy on it and wears dark green trousers.
Judging from Butters's injuries, Nelly is able to fight. According to Bebe Stevens, Nelly would never let the boys see the list, so it can be assumed she is trustworthy. Her ability to fight and her loyalty to the List-Making Committee may be the reason she is the keeper of the lists.
In "The List", Nelly is a member of the girls list making committee. She is in charge of holding onto and protecting lists from non-members.
In "The List", Butters tries to take the list from Nelly by kicking her in the crotch. This has little to no effect on her as she questions what he's doing and after the other boys abort the plan he is seen with his arm in a sling and a black eye.
In "Member Berries" when she called Cartman a "fat fuck", Butters laughed really hard.
In "Douche and a Danish" she was about to fight Butters and was waiting for him to pull his pants up, which he refused to do so. It can be assumed that she doesn't like Butters.
- "Free Willzyx" - Seen at the Denver Aquarium with her family.
- "The List" - As one of the list keepers.
- "Tonsil Trouble" - Cheers during the fight between Kyle Broflovski and Eric Cartman.
- "Canada on Strike" - As one of the people watching Butters' video on her computer.
- "Super Fun Time " - Seen as a part of the class field trip as Emily's partner.
- "The Ring" - Watching the Jonas Brothers concert.
- "T.M.I." - Seen in the hallway, grossed out by the chart of the boys' penis sizes.
- "1%" - Seen during the school assembly.
- "Faith Hilling" - Seen exiting the school with the other students.
- "Jewpacabra" - Seen at the Easter egg hunt.
- "Butterballs" - Seen in the background in the cafeteria.
- "Raising the Bar" - Seen during the "Here Comes Fatty Doo Doo" video, where she is knocked over by Cartman's scooter.
- "Going Native" - Seen at the airport with her mom.
- "A Scause For Applause" - Seen in the background in the school hallways.
- "Let Go, Let Gov" - Seen in the school hallways talking to Tammy Nelson and Emily.
- "The Cissy" - Seen listening to Lorde's new song with Bebe and Millie in Bebe's room.
- "Cock Magic" - Seen in the hallway and on the volleyball game.
- "Stunning and Brave" - Seen in the hallway.
- "Sponsored Content" - Seen in the hallway.
- "Member Berries" - Speaks at the school assembly.
- "Skank Hunt" - Conspires with her fellow female classmates to get back at the boys for Skankhunt42's wrong doings.
- "Wieners Out" - Seen in the stands at the volleyball game.
- "Douche and a Danish" - Seen in the battle between the girls and the boys, preparing to fight Butters Stotch.
- "Put It Down" - Seen while Cartman is singing.
- "Holiday Special" - Seen in the hallway rampaging due to a cancellation of Columbus Day, and seen in the crowd.
- "Hummels & Heroin" - Plays in the bouncy house with Wendy at Marcus's birthday party. Later rallies with Marcus after witnessing his presentation in the school cafeteria.
- "Moss Piglets" - Seen along with Bebe and Nichole when Nathan tells them about the special ed science fair.
- "SUPER HARD PCness" - Seen in the hallway evacuating to the gym.
- "The Problem with a Poo" - Seen in the school assembly.
- "Tegridy Farms" - Seen in the corridor.
- "The Scoots" - Seen fighting for an E-Scooter.
- "Time To Get Cereal" - Seen in the school's playground after evacuation.
- "Bike Parade" - Seen at the bike parade.
- "Let Them Eat Goo" - Seen in the cafeteria.
- "Tegridy Farms Halloween Special" - Seen at the school assembly.
- "Board Girls" - Seen at the school assembly and at the Board Girls Gaming Club.