Preheat oven to 400 degrees. In a large skillet on medium-high heat saute onion in a bit of oil until translucent. Add ground beef or turkey, break into small pieces until cooked through. Drain most of the fat.
Stir in Taco Seasoning Mix, beans, tomato sauce, and corn. Bring to boil. Reduce heat to low and simmer 5 minutes, stirring occasionally. Spoon into 2-quart baking dish. Sprinkle with cheese and Frito chips.
Bake in 400° oven for 5 to 10 minutes until cheese is melted.
To serve, put a few Frito chips in the bottem of a bowl and spoon in the baked taco casserole. Top with your choice of sour cream, green onions, lettuce, and tomatoes.
This casserole can be frozen. Place in freezer BEFORE adding Frito chips and cheese. Allow frozen mixture to thaw, place in large pan and bring to a boil, spoon into 2 quart baking dish, add Frito chips and cheese and bake in 400 degree oven until cheese is melted.