1 tbsp. oil
1/2 c. chopped onion
1 lb. hamburger
1 qt. drained tomatoes
1 pkg. taco seasoning
1 pt. sour cream
1/2 c. sharp cheddar cheese
1/2 lb. mozzarella cheese
1 (7 oz.) pkg. Dorito chips, crushed

Brown hamburger and onion in oil; drain. Blend in tomatoes and taco seasoning. Simmer 10 minutes. Grease 9 x 13 inch pan. Layer half of crushed chips on bottom of pan. Add meat, mozzarella cheese and sour cream. Top with remaining chips. Sprinkle with cheddar cheese. Bake at 350 degrees for 30 minutes or until heated through.