Ravioli Chicken Casserole

1 (24 ounce) package frozen cheese ravioli, cooked and drained
3 cups cooked, cubed chicken
6 medium fresh mushrooms, sliced (optional)
1/2 cup chopped green bell pepper
1/3 cup chopped onion
1 (28 ounce) jar meatless spaghetti sauce
2 cups (8 ounces) shredded mozzarella cheese

In a greased 9 x 13-inch baking dish, layer the ravioli and chicken. Top with mushrooms, green pepper, onion and spaghetti sauce. Cover and bake at 350 degrees F for 20 minutes.

Uncover; sprinkle with cheese. Bake 10 15 minutes longer or until cheese is melted.