Assemble casserole as directed but do not prepare stuffing; refrigerate up to 4 hours. When ready to serve, prepare stuffing as directed on package; spoon over casserole. Cover. Bake 55 min. or until turkey mixture is heated through and topping is crisp, uncovering after 35 min.
Substitute canned fat-free reduced-sodium chicken broth for the Turkey Stock.
Prepare using leftover roasted chicken.