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Nia Moseby (Giovonnie Samuels) is Mr. Moseby's niece. She has a part-time job at the candy counter, filling in for Maddie during her absence.
Her purpose for staying at the Tipton for the summer is so Moseby can get her to behave like a proper girl and so she can learn responsibility. One of Nia's aunts, named Aunt Lilly, tried to make her behave like a proper girl. But she couldn't stand Nia, so she changed her name and moved to Alaska. According to Mr. Moseby, she was expelled from her last school for fighting. In "First Day of High School", she defended Zack from a jock named Vance, who later become her boyfriend In an episode of The Suite Life of Zack and Cody it is shown that Nia is very flexible and athletic.