Place the chicken breasts in the Instant Pot and sprinkle with salt, pepper, garlic powder, and smoked paprika. Pour in the chicken stock, then toss everything together to coat the chicken evenly.
Secure the Instant Pot lid and set the valve to 'sealing'. Select the 'Manual' or 'Pressure Cook' setting on high pressure for 10 minutes. After cooking, allow the pressure to release naturally for 5 minutes, then carefully perform a quick release for any remaining pressure.
Open the lid once the pressure has fully released. Use two forks to shred the chicken right in the pot, mixing it with the juices for extra flavor.