Heat oven to 350°F. Spray 2-quart casserole with cooking spray.
In large microwavable bowl, place pasta-vegetable mixture. Cover with plastic wrap; microwave on High 9 to 11 minutes, stirring halfway through microwave time, until sauce chips are melted and vegetables are cooked. Stir in tuna, soup and milk. Pour into casserole.
In small bowl, toss topping ingredients. Sprinkle over tuna mixture.
Bake 25 to 30 minutes or until hot and topping is golden brown.