Turn the pressure cooker on to sauté mode, add oil and then brown the pork chops on both sides. Turn pot off. Remove meat and deglaze the pot with 1/4 c of your broth.
Put meat back in. Whisk rest of broth and tomato sauce together in a bowl, pour into pot. Add in onion, mushrooms, worc. sauce.
Close lid and steam valve and set to pressure high for 8 minutes. (timing depends on thickness of meat)
Allow to naturally release steam for 2 minutes, then do a quick release. Set Instant Pot on saute again. Remove meat and set aside under foil to stay warm.
In a small bowl mix together half and half and cornstarch and add into the pot allowing liquid to bubble and thicken. Add garlic salt if desired, whisk together. Turn pot off and serve meat and gravy over rice!