Preheat oven to 350°F (175°C) and grease a 9x13 inch baking dish.

In a skillet over medium heat, cook seasoned chicken breasts for 6-7 minutes on each side until golden brown; let cool and dice into bite-sized pieces.

Cook rice according to package instructions until fluffy.

In a large mixing bowl, combine diced chicken, cooked rice, broccoli florets, cheddar cheese, chicken broth, garlic powder, and sour cream; mix thoroughly.

Transfer the mixture to the prepared baking dish and top with extra cheese if desired. Bake for 30-35 minutes until bubbly and golden brown.

Allow to cool for five minutes before serving.