The American Idol mentor had harsh words for the judges this week, which Nicki did not appreciate, according to TV Guide.
"I wish he would just zip his lips and let America make their own decisions," Nicki says.
Jimmy had criticized the judges for being too confusing and too polite in their feedback.
Nicki also thinks Lazaro Arbos has stuck around longer than he should have because people are rejecting the comments Jimmy makes about him.
"Because he comes down very hard on Lazaro [Arbos], America keeps voting for him," Nicki explains. "You don't want to force a decision down [viewers'] throats because they're going to feel compelled to rebel."