Cook the carrots, celery and onion for 5 minutes in 1 tablespoon of olive oil using the saute function on your Instant Pot, stirring occasionally.
Add the chicken and cook for 3 minutes on each side, until lightly browned.
Add the tomato paste, Italian seasoning, and granulated garlic, cooking for one additional minute, stirring occasionally minute.
Turn off the sautee function. Add the remaining ingredients (except for the water, cornstarch and 1 tablespoon balsamic vinegar) to the Instant Pot, stirring to combine.
Cook on high pressure for 6 minutes, then do a natural pressure release.
Remove the chicken, shred or dice, and add back to the pot.
Mix together the water, arrowroot powder, and balsamic until smooth. Pour mixture into the pot, stirring to combine. Serve warm with a generous drizzle of olive oil and freshly ground pepper to taste.