Press the SAUTE button to turn on the saute setting on the Instant Pot.
Wait until the Instant Pot Display says "Hot" and then add oil. When the oil is hot, add chopped onions, celery, and carrots. Stir and cook until the onions are translucent. Then add in the minced garlic and stir for about 1 minute.
Add the chopped chicken into the Instant Pot along with the vegetables.
Add the salt, pepper, and Italian Seasoning, and saute the chicken and vegetables for about 3 - 4 minutes.
Press the Cancel button, and then pour in the chicken broth and egg noodles. Close the lid, move the vent to the "sealing" position.
Press the SOUP / BROTH button to set the Instant Pot to the Soup setting and press the + and - sign to adjust the time to 4 minutes.
After 4 minutes, let the Instant Pot release the pressure naturally for about 10 minutes (which means you do nothing) and then carefully use the quick release method to release the remaining steam. On most Instant Pot models, it means to move the pressure release valve to the VENTING position. (Read the manufacturer's instructions for how to do this for your pressure cooker.)
Turn off the Instant Pot.
Serve the chicken noodle soup in soup bowls.
Garnish with chopped parsley, if desired.
**Before using your Instant Pot, be sure to read the manufacturer's instructions regarding how to use the Instant Pot.**