Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish with olive oil.
In a large mixing bowl, combine the cooked rotini pasta, shredded chicken, broccoli florets, and Alfredo sauce. Mix well until all ingredients are evenly coated.
Add garlic powder, black pepper, salt, and red pepper flakes (if using) to the mixture. Stir until well combined.
Pour the pasta mixture into the prepared baking dish, spreading it out evenly.
Sprinkle the shredded mozzarella and grated Parmesan cheese over the top. If desired, add breadcrumbs for extra crunch.
Cover the baking dish with aluminum foil and bake in the preheated oven for 20 minutes.
Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden brown.
Allow the dish to cool for a few minutes before serving.