Cook zucchini, squash and onion in salted water for 10 minutes; drain. Combine Stove Top stuffing crumbs, seasoning packet and butter - mix well - place half of mixture in bottom of 9x13 baking pan. Mix together sour cream, cream of chicken soup and shredded cheese; add zucchini/squash and mix well. spoon into baking pan on top of stuffing mixture then top with remaining stuffing mix. Bake at 350 degrees for 25 minutes. You can add cooked/shredded chicken for a complete meal.