Preheat the oven to 375ºF. Grease a large 9 x 13" baking dish with avocado oil or ghee and set aside.
Melt 1 Tbsp of ghee in a large skillet over medium high heat. Season the chicken breasts with salt & pepper on both sides, then add them to the skillet. Cook the breasts for a few minutes per side until browned (don't worry about cooking them through), and set them aside on a plate.
Melt an additional Tbsp of ghee in the skillet, and add the vegetables (broccoli, mushrooms, peppers, onion, and garlic). Sauté until tender crisp, about 5 minutes (they don't need to be fully softened).
Stir in the cauliflower rice, and remove the veggies from the heat. Transfer the mixture to the greased baking dish, and layer the chicken breasts over top.
In a small mixing bowl, combine the buffalo sauce ingredients: mayo, buffalo sauce, coconut milk, and spices. Pour the sauce over top of the chicken and vegetables.
Transfer the dish to the oven, and bake for 45 minutes or until the chicken is cooked through and the sauce is bubbly around the edges. Serve hot!