2 lbs. ground beef
2 med. onions, chopped
1 pkg. taco mix
1 (16 oz.) can tomato sauce
2 c. shredded cheese
1 lb. bag Mission Tortilla chips

In skillet, cook beef and onions until meat is brown and onion is tender. Drain. Stir in taco mix and tomato sauce and simmer for 5 minutes. Place 3 cups Mission Chips in 2 quart dish. Top with 1/2 grated cheese, the meat mixture and then remaining cheese. Top with additional 2 cups chips. Bake at 350 degrees for 15 minutes. Garnish with sour cream and sliced black olives, if desired.