Slice onion and cube meat. Heat instant pot to hot on "Sauté" option. Place 1 Tbsp of oil in the hot pot. Add onions and 2 tsp of steak seasoning. Cook until starting to brown/caramelize, stirring occasionally. Remove onions with a spoon. Set aside.
Add 1 Tbsp of oil to the hot pot. Add cubed beef roast and 2 tsp steak seasoning. Stir just enough to sear the meat a little bit. Add worcestershire sauce and beef broth.
Close and lock the lid and make sure the vent on top is closed.
Cancel "Sauté" button and press the "Meat/Stew" button, adjusting the time to 45 minutes.
Let cook. Once finished, turn the vent/quick release valve to the open position until you no longer hear or see steam, and the float valve is down.
Open lid. Using a slotted spoon, scoop the meat out of the instant pot and shred with a fork. Drain the broth/au jus with a fine mesh sieve.
Toast sub rolls with butter (or garlic butter) in a large pan until golden brown. Fill with meat, and top with provolone cheese. Serve with au jus for dipping. Enjoy!