Preheat your oven to 350°F (175°C).
Cook the rotini pasta according to package instructions until al dente. Drain and set aside.
In a large mixing bowl, combine the cooked rotini, shredded chicken, broccoli, Alfredo sauce, garlic powder, Italian seasoning, salt, and pepper.
Transfer the mixture into a greased 9x13-inch baking dish, spreading it evenly.
Top the casserole with shredded mozzarella and grated Parmesan cheese.
Bake in the preheated oven for 25-30 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let cool for a few minutes before serving.