Turn Instant Pot to SAUTE setting.
When the Instant Pot displays says "HOT", add the oil and swirl around.
Add in the Onions, Celery, Peas and Carrots, and saute for 4-5 minutes.
Add the Chicken Broth, and scrape the bottom of the pot so that nothing is sticking. Turn off Instant Pot.
Add the chicken and Poultry Seasoning.
Cover the Instant Pot and set the valve to SEALING.
Hit the SOUP button, and set for 12 minutes.
When the time is up, let the pot sit for 5-10 minutes, then move the valve to VENTING, and remove the lid.
Move the chicken to a cutting board.
Add the frozen tortellini to the Instant Pot, and hit the SAUTE button.
While the tortellini is cooking for 3-5 minutes, shred or chop the chicken.
When the tortellini is done, add the chopped Chicken, Parsley, and Lemon Juice to the Instant Pot.
Salt and pepper to taste, and turn the Instant Pot OFF, and serve.