Grease inside of a 6QT instant pot. Season chicken breasts with salt and pepper to taste. Rinse rice under cool water until the water runs clear.
In order add mushrooms, onion, rice, chicken breasts to the Instant Pot.
Pour broth over chicken breasts. Spread mushrooms soup overtop of chicken breasts. Do not stir.
Set instant pot to MANUAL. Choose HIGH PRESSURE for 10 minutes. (The Instant Pot will take about 15 minutes to reach pressure).
Open the Instant Pot and remove chicken. Stir rice and mushrooms. Shred chicken and return to rice and mix well.
(Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.)