Brown beef along with salt and pepper. Drain off the fat. In a 2 1/2qt casserole dish, add the soups, mushrooms, mixed vegetables, and garlic powder. Blend well. Add ground meat and blend all together. Cover top completely with Tator Tots. Bake in oven on baking sheet (for spills) at 350 degrees for an hour, or until sauce is bubbling rapidly from edges.