Season chicken with salt and pepper and place in pressure cooker. Add water and lock lid. Seal valve and cook at high pressure for 8 minutes. Natural pressure release (this means do not move the valve) for 10 minutes. Quick pressure release (this means move the valve) the rest. Transfer chicken to a plate and cover for with foil. Rest for 5-10 minutes.
You can increase number of chicken breasts to however many you can fit in a single layer in your pressure cooker. Adjust seasons accordingly. Water amount will not need to be adjusted.If cooking from frozen, cook at high pressure for 12 minutes. All other times remain the same.