Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish.
In a large bowl, mix together sour cream, mayonnaise, garlic powder, onion powder, salt, pepper, and paprika.
Fold in the cooked chicken and steamed broccoli until well coated.
Transfer the mixture to the prepared baking dish and spread it evenly.
Top with shredded cheddar cheese and Parmesan cheese.
Bake for 25–30 minutes or until bubbly and golden on top.
Let rest for 5 minutes before serving. Garnish with parsley if desired.