Preheat oven to 350 degrees F. Brown meat in skillet, drain grease, and then spread in bottom of 9x13 baking dish.
Mix soup & milk in bowl & set aside. Layer cheese over meat. Layer beans & mushrooms over cheese and sprinkle with garlic salt & pepper to taste. Cover with a layer of tater tots. Pour soup & milk mixture over tater tots.
Bake for approximately 1 hour or until tater tots are brown & crisp.