Press sauté on the instant pot. Add oil. When oil is hot, add garlic. Stir well and let garlic cook 30 seconds. Add pork and brown on all sides.Press cancel.
Remove pork; add wine. Scrape pot to loosen brown bits. Fit instant pot with trivet. Add broth. Place pork on trivet.
Lock lid; set valve to sealing. Program for manual-high and 90 minutes. Allow for natural pressure release. Once pin drops, open lid and remove pork to a serving platter. Remove trivet.
Sauce
Press sauté. Add balsamic vinegar. Stir well. Remove 1/4 cup liquid from pot and place into a small bowl. Add cornstarch. Stir until cornstarch is dissolved. Pour cornstarch mixture into pot. Stir well and allow to thicken (about 2 minutes).