Place the frozen chicken breasts in the Instant Pot
Add 1 cup of water or chicken broth
Season the chicken if desired
Close the lid and set the valve to sealing
Cook on High Pressure for 12 to 15 minutes for average-sized breasts
Cook for 15 to 18 minutes for large or thick breasts
Let the pressure release naturally for 5 minutes
Turn the valve to quick release to release the remaining pressure
Check that the internal temperature reaches 165°F
Let the chicken rest for a few minutes before slicing or shredding