Press Sauté; heat oil in Instant Pot. Add short ribs in batches; cook about 8 minutes or until browned on all sides.
Remove to plate; season with Italian seasoning, salt and pepper. Drain off all but 1 tablespoon fat.
Add leeks to pot; cook and stir 2 minutes or until softened. Add wine; cook until almost evaporated, scraping up browned bits from bottom of pot. Return short ribs to pot with olives; pour pasta sauce over short ribs.
Secure lid and move pressure release valve to Sealing position. Press Manual; cook at high pressure 30 minutes.
When cooking is complete, use natural release for 10 minutes, then release remaining pressure.
Meanwhile, prepare Parmesan Polenta, if desired.
Serve ribs and sauce with polenta.
Bring 2 cups water to a boil in large nonstick saucepan over medium-high heat.
Gradually whisk in 1 cup instant polenta until smooth and thick. Stir in 1/2 cup grated Parmesan cheese. Season with salt and pepper.