Preheat the oven to 375°F (190°C).
In a large mixing bowl, combine the shredded chicken, cauliflower florets, and broccoli florets.
In a separate bowl, mix together the cream cheese, heavy cream, garlic powder, onion powder, salt, and pepper until smooth.
Pour the cream mixture over the chicken and vegetable mixture and stir until thoroughly combined.
Transfer the mixture to a greased baking dish and top with shredded cheddar cheese.
Bake in the preheated oven for 30-35 minutes, or until the cheese is melted and bubbly.
Let the casserole cool for 5-10 minutes before serving.