Season pork chops with garlic salt and ground black pepper.
Punch sauté over high heat on your instant Pot. Melt butter and add oil. when hot brownpork chops on both sides, 3 to 5 minutes per side. Transfer pork chops to a plate.
Saute onion and mushroom garlic until fragrant; add carrots; cook another 2 minutes; add broth and stir together. Return pork chops to the pressure cooker pot. Set a steamer basket on top of the pork chops and place potatoes in the basket.
Cover the pressure cooker with the lid, lock the lid, bring the cooker to high pressure, and cook for 15 minutes. Release pressure from the pot according to the manufacturer's instructions. Remove potatoes, pork chops and vegetables.
Bring cooker to Sauté; mix corn starch and water and thicken the boiling broth.