Preheat instant pot on the BROWN/SAUTE function. Spray entire pot with nonstick cooking spray. Add olive oil to the bottom of the pot. Sprinkle both sides of pork chops with onion powder and salt.
Add enough pork chops to cover the bottom of the instant pot and cook 2-3 minutes per side or until browned. Remove browned pork chops and add remaining pork chops to brown.
Replace all browned pork chops to the pot and add chicken broth. Press "OFF" and then add the lid to the instant pot and turn to lock. Cook 5 minutes on the "PRESSURE COOKER" setting. (If you are using boneless chops, reduce this to 3 minutes.)
While the pork chops are cooking, in a small bowl or liquid measuring cup, whisk ingredients together for the sauce: ketchup, brown sugar, vinegar, Worcestershire sauce, chili powder and dried mustard.
Once pork chops are done cooking, quick release pressure and open. Remove pork chops and reserve 1/2 cup cooking liquid. Discard remaining cooking liquid. Return instant pot back to BROWN/SAUTE function and add other 1 tablespoon olive oil. Saute onion and garlic 2 minutes or until softened and fragrant. Pour in the sauce and the reserved cooking liquid. Simmer 2 minutes, then add pork chops back in. After another 2-3 minutes, pork chops should be well glazed and sauce should have thickened slightly. Serve with rice.