Add the oil to the instant pot and turn on the saute function.
While the pot is heating, season the beef with the salt, pepper, and Italian seasoning.
When the pan is hot, add it to the instapot and cook until it is browned on all sides.
Add the beef broth to the instant pot and use a spoon to scrape the brown bits from the bottom of the pan.
Add the Worcestershire sauce, garlic, onion, carrots, potatoes, and tomato sauce.
Close the lid and steam valve on the instant pot.
Cook on high pressure for 35 minutes, then allow the pressure to release naturally for 10 minutes before doing a quick release.
Mix together the cornstarch and cold water in a small bowl and stir into the stew until thickened.