Preheat oven to 400F and oil a 9 x 13 baking dish.
Begin by making cauliflower rice.
Chop half of a head of cauliflower into florets and place them in a blender or food processor.
Process until pieces resemble grains of rice.
Place cauliflower rice into a large bowl.
Chop broccoli into florets and add to bowl.
Mix in garlic powder, melted butter, 1 cup cheese, sour cream, cooked chicken, salt and pepper and mix to combine.
Place ingredients from bowl into baking dish and top with remaining cup of cheese.
Bake covered for 25 minutes, or until broccoli is tender.
Remove foil and bake for an additional 5-10 minutes, or until the cheese is crispy enough for your liking.