Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish with cooking spray or butter.
In a large skillet, cook the chicken (if not using pre-cooked chicken) and set aside. Shred the chicken once it’s cooked.
Steam the broccoli until tender but still crisp, about 5-7 minutes. Set aside.
In a large bowl, combine the cream of chicken soup, sour cream, mayonnaise, garlic powder, onion powder, salt, and pepper. Mix well to create the creamy sauce.
Add the shredded chicken and steamed broccoli to the bowl and stir to coat everything evenly with the sauce.
Pour the mixture into the prepared baking dish, spreading it out evenly.
Sprinkle the shredded cheddar cheese and grated Parmesan cheese on top of the casserole.
If desired, sprinkle breadcrumbs over the cheese layer for a crispy topping.
Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbly and the cheese is melted and golden brown.
Serve hot and enjoy!