Put Thinly Sliced Onions in the bottom of a 13 X 9 Dish. Crush Potato Chips all over top of Onions. Shred Cheese over top of Potato Chips. Spoon Cream of Mushroom Soup over top. Make another layer. After you have finished, put 1/2 cup milk in Soup Can and Stir. Pour over all. Bake at 350 Degrees until golden brown and onions are tender.