Preheat oven to 375ºF.
Prepare stuffing as directed on package. Set aside.
Mix soup and mustard in medium bowl; stir in cooked chicken, broccoli and ham.
Spoon mixture into 2 quart casserole dish (9x9 inch baking dish) sprayed with non-stick cooking spray.
Top with cheese slices and then sprinkle on the stuffing.
Bake 35 to 40 minutes or until heated through and cheese is melted.