Cook beef, sausage and onion in large skillet until meat is no longer pink, breaking up with a spoon, about 9 minutes. Drain thoroughly. Season with hot pepper sauce, salt and pepper.
Layer beans, meat mixture and 4 oz. chilies in 9" square baking dish. Cover with cheese. Top with 3/4 cup salsa. Cover and bake until mixture is bubbling and cheese melts, about 35 minutes. Transfer topping to chafing dish or put baking dish on warming tray. Garnish with green onions, olives, avocados and sour cream. Serve hot with potatoes, passing additional salsa.