Season pork chops with garlic powder, seasoned salt, oregano, onion powder, and pepper.
Turn on a multi-functional pressure cooker (such as Instant Pot) and select Sauté function. Melt butter in the hot pot. Add pork chops, working in two batches if necessary, and sear until crispy and brown, 2 to 3 minutes per side. Remove the chops to a plate. Pour in vegetable broth, and deglaze, scraping the browned bits from the bottom of the pot with a wooden spoon.
Place a trivet at the bottom of the inner pot and stack the pork chops on top. You do not want the pork chops resting in the liquid or the seasoning will wash off. Close and lock the lid and turn the pressure valve to Sealing. Select high pressure according to manufacturer's instructions; set timer for 8 minutes. Allow 10 to 15 minutes for pressure to build.
Release pressure using the natural-release method according to manufacturer's instructions for at least 10 minutes. Remove the pork chops and let rest while you make the gravy.
Select Sauté function on the Instant Pot. Whisk sour cream into the broth and allow the liquid to simmer, stirring occasionally, until gravy reduces by half and thickens, 10 to 15 minutes. Pour gravy over chops and serve.