HEAT oven to 375°F.
POUR sauce into 13x9-inch baking dish. Stir in 1/4 cup (4 Tbsp.) Parmesan. Add chicken; turn to evenly coat both sides of each breast with sauce. Cover.
BAKE 30 min. or until chicken is done (165ºF). Meanwhile, cook spaghetti as directed on package, omitting salt.
TOP chicken with remaining cheeses; bake, uncovered, 5 min. or until mozzarella is melted.
DRAIN spaghetti. Serve topped with chicken and sauce.