Start by seasoning the pork roast with your chosen spice mix. Rub the whole roast with spices and garlic. Now, set your Instant Pot to "saute", add the olive oil, and brown the roast on all sides. 1-2 minutes per side.
Add chicken broth to the Instant Pot, close the lid, set steam release knob to "sealing", and set for manual high for 90 minutes.
When time is up, allow the pressure to release naturally for at least 10 minutes and then you can use quick release if you wish. Meanwhile, set your oven to broil.
Remove the roast from the Instant Pot and shred it with two forks. Place the shredded pork on a parchment-lined baking sheet. Brush the shredded pork with the barbecue sauce and place in the oven to broil for 8-10 minutes or until the edges are browning and caramelized.