Preheat the oven to 375°F (190°C).

In a skillet, heat olive oil over medium heat.

Add the chicken breasts and cook until browned, about 5-7 minutes per side.

Remove the chicken from the skillet and let it cool for a few minutes before cutting into bite-sized pieces.

In a large bowl, combine the cooked chicken, broccoli, cauliflower rice, garlic, onion powder, salt, and pepper.

In a separate bowl, whisk together heavy cream and half of the shredded cheddar cheese.

Pour the creamy mixture over the chicken and vegetables, mixing until well coated.

Transfer the mixture to a greased baking dish.

Sprinkle the remaining shredded cheese on top before baking.

Bake for 25-30 minutes, or until the cheese is bubbly and golden brown.

Let the casserole cool for a few minutes before serving.