Heat oven to 350°F. Spray 13x9-inch (3-quart) glass baking dish with cooking spray.
In large bowl, gently mix together cooking sauce, stuffing, turkey and vegetables. Spoon evenly into baking dish. Spoon potatoes evenly over stuffing mixture; spread to cover stuffing. Sprinkle with onions.
Bake about 30 minutes or until bubbly around edges and hot in center.