Preheat the oven to 375°F (190°C). Lightly grease a baking dish with olive oil or non-stick spray.
Steam the broccoli until tender but still bright green. Drain excess moisture.
Prepare the sauce: In a bowl, whisk Greek yogurt, chicken broth, garlic powder, onion powder, paprika, salt, and pepper until smooth.
Combine ingredients: Add chicken, rice, broccoli, and half of the mozzarella cheese to the sauce. Mix well.
Assemble casserole: Transfer the mixture into the prepared baking dish and spread evenly.
Add topping: Sprinkle remaining mozzarella and Parmesan cheese on top.
Bake uncovered for 25 to 30 minutes, until bubbly and lightly golden.
Rest & serve: Let the casserole rest for 5 minutes before serving. Garnish with parsley if desired.