Sauté onions- Set the Instant Pot to 'sauté'. Add the olive oil and onions to the stainless steel inner pot of the Instant Pot, and sauté for 4-5 minutes, until onions are soft and transluscent.
Add ground beef- Add the ground beef (or Beyond Beef) to the pot with the worcestershire sauce, and break it up with a spatula. Sauté for 3-4 additional minutes (Beyond Beef) or 6-7 minutes (ground beef), until cooked through. Add 1-2 cups of stock to the pan, scraping up the bottom to ensure nothing is stuck.
Other ingredients- Add the rest of the stock, diced tomatoes, green chilies, corn, black beans, taco seasoning and bell peppers.
Cook- Place the lid on the Instant Pot, set the valve to the 'sealing' position, and pressure cook on high pressure for 5 minutes. When the cooking cycle has completed, allow the Instant Pot to sit for 10 minutes (10 minute natural pressure release), before carefully releasing the remaining pressure.
Serve- Top soup with shredded cheese, tortilla strips, cilantro and avocado, or your favorite toppings!