Preheat your oven to 400°F (200°C).
Chop the cauliflower into small bite-sized florets and toss with avocado oil, sea salt, and black pepper on a baking sheet.
Roast the cauliflower for 15 minutes until it begins to soften and brown slightly.
While cauliflower roasts, combine the shredded chicken, Greek yogurt, buffalo sauce, garlic powder, and onion powder in a medium mixing bowl.
Finely dice the celery and fold it into the chicken mixture for added texture.
Transfer the roasted cauliflower to a small oven-safe baking dish and spread the buffalo chicken mixture evenly over the top.
Sprinkle the shredded cheddar cheese over the chicken layer.
Bake for 10-12 minutes until the cheese is melted and the sauce is bubbling around the edges.
Allow to cool for 5 minutes before serving.