PREHEAT OVEN to 350. In a 14-inch pan, sauté onion in butter. Add squash and cook until slightly softened. Squash will release a lot of water, which must be drained. Mix squash and onion with cheese, soup, and green chilies and place in oiled casserole dish. Cover with bread crumbs and bake about 30 minutes or until hot throughout. Makes 10 servings.