Spray a 9x13-inch baking dish with non-stick spray.
Add the chicken, olive oil, onion, garlic, seasonings, wild rice, orzo, carrots, celery, and broth into the baking dish. Gently stir to combine and ensure the chicken isn’t overlapping.
Place the slices of butter over the top.
Cover tightly with foil and bake for 65 minutes.
Carefully remove the foil, stir slightly, and bake for an additional 20 minutes, or until the rice is tender.