Brown the ground beef together with the onion until the meat is no longer pink and the onion is translucent. Add the envelope of taco seasoning mix, tomato sauce and Rotel and heat through. Stir in the cream of mushroom soup and Ranch Style Beans. Allow to simmer for about 10 minutes.

Spray a large 12-inch skillet bottom with cooking spray and line the bottom with the flour tortillas. Layer half of the hamburger mixture on the tortillas and top with crushed tortilla chips until completely covered. Sprinkle half the cheese over the top of the tortilla chips. Add another layer of the meat mixture and top with remaining cheese. Bake covered with foil in the oven at 350 degrees for 35 minutes. Uncover and bake an additional ten minutes until cheese is bubbly. Serve with tortilla chips.

Add a dollop of sour cream to top everything off.