1 lb. ground beef
1/2 c. finely chopped onion
2 (8 oz.) cans tomato sauce
4 oz. can green chilies
2 tsp. oregano
8 oz. pkg. tortilla chips
8 oz. cubed Monterey Jack cheese
8 oz. sour cream
1/3 c. shredded cheddar cheese

Heat oven to 350 degrees. Brown beef with onions in skillet; drain. Add tomato sauce, chilies and oregano. Cook over low heat for 10 minutes; remove from heat. In a greased 2 1/2 quart casserole dish, layer half of each of the following: tortilla chips, Monterey Jack cheese and beef mixture. Repeat layering. Bake 20 to 25 minutes or until heated through. Remove from oven, top with sour cream (to edges) and sprinkle with cheddar cheese. Bake until cheese is melted, 4 to 5 minutes. Serve immediately. Serves 6 to 8.