Turn instant pot to saute and add the oil. Once the oil is hot, add the ground beef, onion, green bell pepper, and garlic. Cook until meat is no longer pink.
Add the remaining ingredients in the order listed above.
Set the instant pot to manual, high pressure for 10 minutes.
Once cooking is done, allow the pressure to release naturally for 10 minutes, then quick release.
Serve in deep dishes or bowls, with sour cream and cheddar cheese on top.