Select the sauté function on the Instant Pot.

When pot is hot, add olive oil.

Add sliced onions to the pot and sauté until they become translucent or about 2-3 minutes.

While the onions are cooking, rub the seasoning salt all over the pork loin.

Push the onions to the sides of the pot.

Add a bit more olive oil to the pot if needed, then add the seasoned pork loin.

Sear on all sides until browned, about 2-3 minutes per side.

Remove pork from the Instant Pot but keep warm.

Add the water to the pot, scraping the bottom to remove any cooked-on pieces. Return the pork loin to the pot.

Pour 1 cup of barbecue sauce over the pork loin.

Lock the lid of the Instant Pot in place and set the valve to sealing.

Cook on high pressure for 35 minutes.

Once the cooking time is up, allow for a natural pressure release for about 10 minutes, then carefully quick release any remaining pressure.

In the Instant Pot, shred the pork with two forks. Pour the remaining barbecue sauce over the pork and toss to coat.

Serve the shredded pork loin as it is or on toasted buns.