Preheat your oven to 350°F (175°C). Cook your rice according to the package instructions so it’s ready to layer in the baking dish. Spread the rice evenly across the bottom to help soak up the sauce later.
Heat olive oil in a large skillet. Pat the chicken thighs dry, then season with salt, pepper, and garlic powder. Brown them skin-side down for about 15 minutes, then flip and brown the other side for another 15 minutes. This step builds rich flavor and keeps the chicken juicy.
In a bowl, whisk together the cream of mushroom soup, milk, garlic powder, salt, and pepper until smooth. Stir in the fresh sliced mushrooms and the remaining minced garlic. This will form the silky sauce that “smothers” the chicken.
Lightly grease your baking dish with olive oil. Spread the cooked rice evenly on the bottom. Place the browned chicken thighs on top of the rice. Pour the creamy mushroom sauce over the chicken, covering it as much as possible. Cover tightly with foil and bake for 45–50 minutes.
Remove the foil and bake for an additional 20 minutes so the top browns and the sauce thickens. Let the dish rest for a few minutes before serving to help the sauce settle.