Mix mostaccioli, sauce, 1 cup of the cheese and vegetables. Spoon into 13x9-inch baking dish; sprinkle with remaining cheese. Bake at 375ºF for 20 to 25 minutes or until thoroughly heated.
*Great Substitute: Substitute 1 cup each thinly sliced red and green peppers for 1 cup each of the squash and zucchini.