PREHEAT oven to 375°F. Pour spaghetti sauce into 13x9-inch baking dish; set aside.
MIX 1/2 cup of the cheese and the bread crumbs in separate shallow dish. Dip chicken in butter, then in cheese mixture, turning to evenly coat both sides. Place over spaghetti sauce in baking dish.
BAKE 30 min. or until chicken is cooked through; sprinkle with remaining 1 cup cheese. Bake an additional 5 min. or until cheese is melted. Serve over spaghetti.