Place chicken and/or bones into the instant pot.
Add onion, carrots, garlic and celery. Add water to cover, do not go above the max fill line. Add vinegar, let stand 30 minutes
Place the valve in the sealed position. Use manual pressure for 120 minutes with natural release.
Optional: Once pressure is released, add parsley and let stand for 10 minutes.
Place chicken bones into a large stock pot.
Add onion, carrots, garlic and celery. Add water to cover, add vinegar, let stand 30 minutes
Bring to a boil and remove the foam that floats to the top. reduce heat, cover and simmer for 12 to 24 hours.
Optional: Add parsley the last 10 minutes of cooking.