01 - Preheat the oven to 375°F and lightly grease a 9x13-inch baking dish.
02 - Boil salted water and cook the pasta for 2 minutes less than package instructions, then drain and set aside.
03 - In a large mixing bowl, combine cooked pasta, chicken, broccoli, Alfredo sauce, garlic powder, black pepper, and salt. Mix thoroughly.
04 - Pour half of the mixture into the prepared baking dish, then sprinkle with half of the mozzarella and Parmesan cheeses.
05 - Add the remaining pasta mixture on top, then finish with the remaining mozzarella and Parmesan cheeses.
06 - Cover with aluminum foil and bake for 20 minutes. Remove foil and bake an additional 10 to 15 minutes until cheese bubbles and turns golden.
07 - Allow to rest 5 minutes before serving. Optionally, garnish with chopped fresh parsley.