Place the ingredients in the instant pot in this order: chicken stock (or water), chicken, onion powder, garlic, powder, paprika, salt, BBQ sauce, grated onion, brown sugar and Worcestershire sauce. Do NOT stir. You want the water to stay on the bottom of the pot so the instant pot comes to pressure.
Place the lid on the instant pot making sure the valve is in the sealing position. Press manual (high pressure) and set to 15 minutes. Let the pressure naturally release for 10 minutes. Then quick release the venting position to release the remaining pressure and open the pot.
Remove the chicken and shred it. If necessary, reduce the liquid by pressing the "saute" button and simmering the sauce, stirring often, until thickened. Add the chicken back to the sauce before serving.
Add more BBQ sauce if desired. Shred and enjoy on sandwiches, salads, BBQ plates and more!