Sear the roast w/ olive oil on “Saute” mode in instant pot. Pour in broth and juice into the pressure cooker, lifting roast slightly to allow juice underneath. Sprinkle both packets on roast. Top with butter and pepperoncinis. Replace lid. Cook at high pressure on manual for 90 minutes. (Do not allow warming cycle to come on when finished), use the natural release for 15 minutes, then switch to quick release. Enjoy the tender, flavorful roast in no time!