Place the oil in the Instant Pot and select “Sauté”. Then add the garlic and cook for about 1 minute. Add the onion and mushrooms and cook for about 4-5 minutes.
Add lamb chops, salt and black pepper and cook for about 5 minutes or until browned from all sides.
Select “Cancel” and stir in remaining ingredients.
Secure the lid and cook under “Manual” and “High Pressure” for about 15 minutes.