Brown ground beef with chopped onion and drain fat. Add salt & pepper, tomato sauce, chopped olives and chili powder. In a 11/2 qt casserole dish, layer - starting with a small amount of meat mixture, then 1 tortilla, cover with 1/5-1/6 meat mixture, followed by 1/5-1/6 of grated cheese. Repeat till all ingredients are assembled. Pour 2/3 cup water over assembled casserole, cover and bake for 30 minutes at 350 degrees.