Sprinkle or rub the chicken breasts with seasoned salt.
Pour water into the Instant Pot inner pot. Add the onion, Worcestershire sauce and liquid smoke. Place the chicken breasts into the liquid.
Lock the lid and set the vent to "sealing". Press the Poultry button, or manually set the cook time to 12 minutes (15 minutes if chicken is frozen).
When cooking is complete, naturally release pressure for 10-15 minutes, then do a quick release.
Remove the chicken from the pot and discard the cooking liquid. Shred the chicken with a fork and return to the empty Instant Pot. Add the BBQ sauce and stir. Allow it to heat up on the “stay warm” setting for 5 minutes before serving.
Notes
Don't add the BBQ sauce to the Instant Pot while cooking the BBQ chicken. It will just be a soupy mess at the end.
Skip the extra step of defrosting frozen chicken for this Instant Pot shredded BBQ chicken and put it right into the Instant Pot. All it needs is enough water in the bottom to bring it up to pressure without burning.
If you want to keep the chicken whole just brush the BBQ sauce onto the tops of the chicken and broil it for 3 minutes to make the sauce bubbly and char it slightly.
You can check the internal temp of the chicken. It should be at least 165°F(74°C) for it to be safe to eat.