Season the chicken with salt and pepper. Layer the chicken, onion powder, rice and 1/4 cup cheese in a 6 quart Instant Pot®. Pour the broth over the cheese and spoon the soup on top (the order is important, so don't stir until after the cooking is done).
Lock the lid and close the pressure release valve. Pressure cook on High pressure, setting the timer to 6 minutes (timer will begin counting down once pressure is reached- it takes about 10 minutes). When done, press Cancel and use the quick release method to release the pressure.
Add the broccoli and stir well, then sprinkle with the remaining 1/4 cup cheese. Close the lid and let stand for 10 minutes or until the rice is tender and the broccoli is tender-crisp. Season to taste.