Preheat the oven to 400°F (200°C).
Lightly grease a 9×13-inch casserole dish to prevent sticking.
Spread the cubed chicken evenly across the bottom of the dish.
In a mixing bowl, combine water (or broth), instant rice, cream of chicken soup, cream of celery soup, and cream of mushroom soup. Stir until smooth.
Pour the rice mixture over the chicken, spreading it evenly.
Season generously with salt and pepper.
Place butter slices evenly on top.
Cover the dish tightly with aluminum foil.
Bake for 40–50 minutes until the rice is tender and chicken is cooked through.
Remove the foil and bake for an additional 5–10 minutes until golden and bubbly.
Let rest for a few minutes before serving.
