1Heat oven to 400°F. Place cereal in food-storage plastic bag or between sheets of waxed paper; crush with rolling pin. Set aside.
2Cook and drain macaroni as directed on box. In ungreased 2-quart casserole, stir soup, tuna, vegetables, milk, salt and pepper until blended. Stir in macaroni. In small bowl, mix crushed cereal and melted butter with fork; sprinkle over mixture in casserole.
3Bake uncovered about 30 minutes or until bubbly around edge and hot. Sprinkle with cheese; let stand 5 minutes before serving.