Start by preheating your oven to 350°F (175°C).
Cook the rigatoni in a large pot of boiling salted water until it is slightly less cooked than al dente, about 3-4 minutes less than the package directions.
Add the broccoli florets to the pasta during the last 3 minutes of cooking to soften slightly.
Drain the pasta and broccoli well and transfer them to a 9×13-inch baking dish.
To the baking dish, add the shredded chicken, Alfredo sauce, garlic powder, salt, and pepper. Stir everything together to distribute the ingredients evenly.
Sprinkle the top with the shredded mozzarella and grated Parmesan cheeses.
Bake in the preheated oven, uncovered, for about 25 minutes, or until the cheese on top is melted and golden.
Allow the dish to cool for a few minutes before serving to let the flavors meld together.
Prep Time: 15 mins | Total Time: 40 mins | Servings: 6