She was played by Molly Hagan, who also played Hilda Lake in Murder 101: College Can Be Murder.
Nancy Dalton is the psychotic mother of Robbie Dalton, who had been stalking actress Nina Preston. Nancy is very protective of her only son, willing to do anything for him. In one case (as later revealed), Nancy even responded to Robbie's emails to Nina, posing as the actress to fulfill his twisted fantasy.
Feeling that Nina broke her son's heart, Nancy resorted to stalking Nina herself, and got herself invited on the set of one of her acting gigs. Nancy planned to kill Nina, and she appeared and stabbed a right hand man of Nina, who managed to survive. After that, the evil Nancy entered Nina's trailer and faced the actress, all while revealing herself as Robbie's mother and telling her that she hurt Robbie. The twisted villainess attempted to kill Nina with her knife, only for Nina to toss a cup of hot coffee in her face. A long pursuit followed, with Nancy relentlessly searching for Nina. She finally caught Nina, but at that moment, Beth appeared and held Nancy under arrest.