Preheat oven to 400 degrees F. Spray a 3-quart baking dish with cooking spray and set aside.
In a large bowl, combine uncooked chicken, frozen broccoli, uncooked macaroni and cheese.
1 lb. boneless skinless chicken breast or tenderloins, diced into bite-sized pieces, 1 package package frozen baby broccoli florets (about 5 cups total), 1 cup uncooked elbow macaroni, 1 cup grated cheddar cheese
In a separate bowl, whisk together soups, broth, and garlic powder. Pour wet ingredients into the chicken mixture and stir to combine. Season with salt and pepper, to taste.
1 10.5 oz. can condensed cream of chicken soup (NOT diluted), 1 10.5 oz. can condensed cream of celery soup (NOT diluted), 1 ½ cups chicken broth, ½ teaspoon garlic powder, Salt and pepper, to taste
Transfer to the prepared baking dish.
In a small bowl, toss dry stuffing mix with melted butter. Sprinkle over top of the casserole.
2 cups dry stuffing mix, 2 tablespoons butter, melted
Cover and bake for 30 minutes. Remove cover and continue baking for 10-15 more minutes, or until pasta is tender, chicken is cooked through, and topping is browned. Let stand for 5 minutes before serving.