Frito Casserole

I remember having this as a child, and loving it!  And luckily for me, my mom put it into our family's cookbook.  It was a huge hit with my little family tonight.  It is so yummy and so, so easy!  Enjoy!

Frito Casserole
1 med. onion, chopped
1 lb. hamburger
1 (7 oz.) bag Fritos
1 can chili
Sliced olives (we didn't use these.  My fam isn't a huge fan.  Either way is great)
1 1/2 c. grated cheese
1 small can tomato sauce
Brown meat and onion.  Layer Fritos, then hamburger mixture, chili, olives, and tomato sauce.  Sprinkle cheese last.  Bake at 350 degrees for 30 minutes.  Do not over bake.