LOS ANGELES — Now it’s war: Nickelodeon, once again winning the children’s ratings race against Disney Channel, has decided to throw its weight behind ... a princess.

Nickelodeon has always had its share of magical kingdoms, but this Viacom-owned cable network has tended to leave the princess business to Disney. (And what a business it is, generating an estimated $5.5 billion a year in merchandise revenue alone.) But here comes “Nella the Princess Knight,” which Nickelodeon will introduce on Monday in a programming block for preschoolers.

The self-designated Princess Police, mostly academics who use Snow White, Sleeping Beauty and their slender ilk to make points about their negative impact on young girls, have been a perennial thorn in Disney’s side, even as the company has introduced black and Latina royals, along with a preschool one, “Sofia the First.” Will Nickelodeon now find itself in a similar position?

Maybe not. The self-empowered Nella pushes boundaries, at least for television aimed at 2-year-olds, in the areas of race and gender. She is biracial, with a black father and a white mother, a decision informed by Nickelodeon research indicating that most children under 12 will be nonwhite by 2020 and that already 17 percent are biracial. The character also mashes together traditional boy and girl gender norms.