The Fairly OddParents (2001)

Despite all the ways Vicky has tortured Timmy, it's only when she accidentally erases a videotape that Mom and Dad actually fire her. Determined to get a job, Vicky decides she wants to be mayor and takes over the city. As she's ready to make Vickyville a whole new country, Timmy, who's happy for the first time, realizes he's got to get Vicky out of office and back as his babysitter in order to maintain peace.