Heat oven to 350°F. In 10-inch skillet, cook ground beef over medium-high heat 5 to 7 minutes, stirring occasionally, until thoroughly cooked; drain. Stir in pepperoni and pizza sauce. Cook 2 to 3 minutes over medium heat until hot. Stir in Italian cheese blend and 1 cup of the Cheddar Monterey Jack cheese blend until melted.