2 tablespoons butter
1 pound ground beef
1 medium onion, chopped
2 eggs
1 cup half-and-half
2 teaspoons diced green chiles
1 (8-ounce) can tomato sauce
1 (1.5-ounce) package taco seasoning mix
1/2 cup water
7.5 ounces nacho-flavored tortilla chips
2 cups shredded Monterey Jack cheese
1 cup sour cream
1/2 cup grated cheddar cheese

Heat oven to 350 F. In a 10-inch skillet over medium heat, melt butter. Add ground beef and cook until beef starts to brown. Add onions and continue stirring until beef is cooked through and onions are tender.       Drain and set aside. In a bowl, beat eggs and blend in half-and-half. Stir in chiles, tomato sauce, taco seasoning and water. Mix well. Spread half the chips in a greased 2-quart casserole dish. Top with half the ground beef followed by half the Monterey Jack and half the egg mixture. Repeat layers. Bake 25 to 30 minutes. Remove from oven and spread sour cream over the casserole, sprinkling cheddar on top. Return to oven for 5 minutes or until cheddar melts. Serve with tortilla chips.