If using chuck roast and not already cut stew meat, cut the beef into 1 1/2 to 2 inch cubes.
Heat 1 tablespoon of the olive oil in the Instant Pot using saute mode. When the pot is hot, add half of the beef in a single layer. Sprinkle the beef with half of the salt and pepper.
Brown the beef on the first side, without moving it, for 4 minutes or until it is browned and releases easily from the bottom of the pot. Flip the beef pieces and brown on the second side for about 4 minutes more. Remove the beef to a clean bowl.
Add the remaining 1 tablespoon olive oil to the pot. Brown the second half of the beef, seasoning with the remaining salt and pepper, about 4 minutes per side. Remove the browned beef to the bowl with the first half of the beef.
Add the onion to the Instant Pot and saute for 2-3 minutes, until it begins to soften. Add the garlic to the pot, press cancel to turn off the heat, and cook, stirring, for 30 seconds.
While the Instant Pot is hot, deglaze the pot by pouring in 1 cup of the beef broth and scraping up any browned bits from the bottom of the pot. Pour in the remaining 2 cups of broth.
Add the tomato paste, Worcestershire sauce, Italian seasoning, thyme and bay leaf and stir to combine. Add the beef back to the pot, along with any juices from the bowl. Place the carrots and potatoes on top of the beef. Do not stir.
Close the Instant Pot lid and turn the steam release valve to the sealing position. Press the Manual/Pressure Cook button and set the cook time to 35 minutes at high pressure. The Instant Pot will take 10-15 minutes to reach pressure and then the cook time will begin counting down. When the cook time ends, allow the pot to naturally release for 10 minutes by leaving the Instant Pot alone. Then quick release any remaining pressure by carefully turning the steam release valve to the venting position using the handle of a long spoon.
Open the Instant Pot lid. Remove the bay leaf.
Thicken the stew by stirring together 2 tablespoons cornstarch and 2 tablespoons water in a small bowl. Pour this mixture into the Instant Pot and turn on saute mode. Allow the stew to simmer, stirring occasionally, until slightly thickened. Be careful to not break up the vegetables as you stir.