Set Instant Pot to Sauté mode. Once the Instant Pot displays 'Hot', add oil, onion, garlic and crushed red pepper. Sauté for a min.
Add grape tomatoes, pasta, pasta sauce, half of the basil leaves, salt and 1 cup of water. Stir well.
Set Instant Pot to Manual(High) 4 mins with pressure valve set to sealing.
Quick Release. Stir once again. Add fresh mozzarella cheese and balsamic vinegar.
Serve hot garnished with more chopped basil and shredded parmesan.