Plug in your Instant Pot and press the Saute button. Add the oil and chopped onion and garlic. Saute, stirring occasionally, until onion is very fragrant and begins turning golden-brown around the edges, about 3 to 4 minutes.
Place the boneless skinless chicken breasts in the Instant Pot and brown on one side 3 to 4 minutes. Flip and brown on the other side another 3 minutes (note: don’t cook the chicken all the way through just yet. We are just searing the meat for now to trap in some moisture).
After all of the chicken has browned, pour in broth, seasoning and salt.
Secure the lid on the Instant Pot and select Manual or Pressure Cook and be sure the pressure cooker is on the High Setting. Set the time for 8 minutes, leaving the vent sealed. After pressure cooker has run its course, use the quick release valve to immediately release pressure manually, then open the lid.
Use tongs to transfer chicken to a cutting board. Use two forks to shred the chicken, then place the shredded chicken back into the Instant Pot with the juices. Allow meat to sit about 5 minutes to soak up the juices.