In a small bowl, combine the bbq sauce, brown sugar, garlic powder, onion powder, and salt.
Add the chicken stock to the Instant Pot and add the chicken breasts.
Add the bbq sauce mixture on top of the chicken breasts. Do not stir.
Place the lid on, turn the knob to sealing, and pressure cook (HP) for 10 minutes. Natural release for 10 minutes before quick releasing.
Remove the chicken breasts and shred them with two forks.
Meanwhile, turn on saute mode on the Instant Pot and allow the liquid to cook down so it coats the shredded chicken better. Allow it to cook down to your desired consistency.
Add the shredded chicken back to the sauce in the Instant Pot and toss to coat.