Set the Instant Pot to the Saute function (press the Saute Button on the front of the pot). Once hot, add the olive oil.

Add the chopped celery, carrots, and onion. Sprinkle with a pinch of salt. Saute the veggies until translucent and slightly soft, about 5 minutes.

Add the sliced mushrooms, uncooked rice, and minced garlic. Stir to combine the ingredients. Add the lemon juice and parsley. Press the Cancel button to turn off the saute function.

Add the broth to the pot. Use a wooden spoon to scrape the bottom of the Instant Pot, making sure there aren't any bits left on the bottom.

Season the chicken breasts with salt and pepper. Add the chicken to the pot.

Place the lid on the Instant Pot and set to pressure cook for 10 minutes (Manual, High Pressure). Move the valve on top to Sealed. Now, sit back and relax as the Instant Pot cooks the soup for 10 minutes. Keep in mind, it will take a few minutes for the pot to come to pressure before the cooking begins.

Once the pressure cooking is over, allow the Instant Pot to naturally release the pressure from the pot for 10 minutes.

After 10 minutes, perform a quick release: move the steam release valve on top of the lid from Sealed to Venting. The remaining steam in the Instant Pot will quickly pour out. Once all the pressure has been released, open the lid.

Remove the chicken and shred.

Return the shredded chicken to the pot, add the cream, and taste for seasoning (adding more salt or pepper as needed). Use the Saute function if the soup needs to be heated further after adding the cream. Serve warm.