In a large mixing bowl, combine the uncooked rotini pasta, shredded chicken, broccoli florets, Alfredo sauce, chicken broth, garlic powder, and onion powder. Stir until all ingredients are well combined.
Season the mixture with salt and pepper to taste.
Transfer the mixture into a greased 9x13 inch baking dish, spreading it evenly.
Sprinkle the mozzarella and Parmesan cheese evenly over the top of the casserole.
Cover the dish with aluminum foil and bake in the preheated oven for 25 minutes.
After 25 minutes, remove the foil and bake for an additional 15 minutes or until the cheese is bubbly and golden brown.
Once done, take the casserole out of the oven and let it sit for about 5 minutes before slicing.
Garnish with chopped fresh parsley, if desired, before serving.