In the series
Nellie was a wealthy girl who had long blonde curly hair and always wore fashionable dresses. She was frequently spoiled by her snobbish and overbearing mother Harriet, and she could also be equally as snobbish, very cruel, elitist, callous, manipulative and a bully. She often feuded with Laura Ingalls, one of Little House's main protagonists, while both girls were growing up.
Nellie later began maturing and her attitude improving when she met, then later married, Percival Dalton after he was hired to help run Nellie's restaurant and hotel later in the TV series. Nellie and Laura end up becoming friends as adults and Laura's mother Caroline helped deliver Nellie's twin children. Nellie, Percival and their children eventually leave Walnut Grove and move to New York City to run Percival's family business, but Nellie returns in the show's final season for a visit with her family, where she first meets her parents' newly-adopted daughter Nancy, who has been made into a younger version of Nellie by Harriet and proves to be even worse than Nellie was at Nancy's age.