Brown 2 pounds lean hamburger. Slice enough potatoes, depending on how large the casserole. Layer potatoes and hamburger into casserole. Add Old El Paso green chilies, chopped, depending on how "hot" you desire. Add 1/2 teaspoon salt. Mix 1 can of mushroom soup with a can of water and pour over casserole. Bake until potatoes are tender. Then top with cheese and bake until slightly brown.