Preheat the oven to 350°F (175°C).
In a large mixing bowl, combine the cooked turkey, stuffing mix, onions, celery, garlic powder, salt, and pepper.
Add the chicken broth and cream of mushroom soup, stirring until well combined.
Transfer the mixture into a greased 9x13 inch baking dish.
Sprinkle the shredded cheese evenly over the top.
Cover the dish with aluminum foil and bake for 30 minutes.
Remove the foil and bake for an additional 15–20 minutes, or until the cheese is bubbly and golden brown.
Let it cool for a few minutes before serving.