In a small bowl, combine 1 tablespoon of the olive oil, rosemary, garlic, thyme, sage, pepper and salt.
Pat the pork roast dry with paper towels. Leave the strings on if you want to retain the shape. Strings help with more uniform cooking as well.
Rub the herb paste over the pork roast.
Select the Sauté button to heat the Instant Pot.
Once heated, add the remaining tablespoon of olive oil.
Place the pork roast into the Instant Pot, and sear until browned nicely on all sides.
Remove the pork roast from the Instant Pot and place on a plate.
Pour the broth slowly into the Instant Pot, deglazing the bottom by scraping any browned bits from the bottom with a wooden spoon. Add in the onions.
Press the cancel button on the Instant Pot.
Place the Instant Pot trivet in the bottom of the Instant Pot.
Place the browned roast on top of the trivet.
Cover the Instant pot, lock on the lid according to the manufacturer's directions.
Set the steam release valve to Sealing.
Select high pressure and make the cook time to 60 minutes.
Once the 60 minutes has elapsed, let the pot naturally release for another 20 minutes. This is a great time to prep your vegetable side dish etc.
If needed, do a quick release according to the manufacturer's directions.
Remove the roast and plate. Remove the strings, slice and serve!
Once you remove the pork from the Instant Pot, whisk 2 tablespoons of cornstarch into 1/3 cup of cold water. Turn the Instant Pot to sauté, then whisk just enough of the cornstarch slurry into the drippings in the pot to thicken it. Cook a couple of minutes more, whisking. Taste test, add salt and pepper to taste, then transfer to your gravy server.
If you want a roast that shreds, you will need to cook it another 60 minutes on high pressure, for a cook time of 120 minutes on high pressure.