1 lb. ground beef, browned & drained
1 med. onion, chopped
1 lb. Velveeta cheese
1/2 c. milk
1 can Rotel tomatoes
1 med. bag Doritos
2 cans cream of mushroom soup

Mix first 5 ingredients. Layer mixture and Doritos. Pour soup over layers. Bake at 350 degrees until bubbly. Serves 4 to 6.