Set the Instant Pot to the Sauté function. Add olive oil. When hot, add the cubed chicken and cook until lightly browned on all sides, about 4 minutes. Remove chicken and set aside.
Add the chopped onion to the pot and cook until softened, about 3 minutes. Add the minced garlic and cook for 1 minute more until fragrant. Press Cancel.
Pour in the chicken broth, scraping the bottom of the pot well with a wooden spoon to release any browned bits (this prevents the Burn notice).
Stir in the orzo, Italian seasoning, salt, and pepper. Do not stir in the chicken yet.
Place the browned chicken pieces on top of the orzo mixture. Do not stir them down into the liquid.
Secure the lid and set the vent to Sealing. Select Manual/Pressure Cook on High for 4 minutes.
When the cooking cycle finishes, allow a Natural Pressure Release (NPR) for 5 minutes, then carefully quick release any remaining pressure.
Open the lid. Stir in the cream cheese cubes until fully melted and smooth.
Stir in the heavy cream and Parmesan cheese until the sauce is creamy. If the sauce is too thick, add a splash more broth or cream.
Serve immediately, garnished with fresh parsley.
Notes
To prevent the ‘Burn’ notice, make sure you deglaze the bottom of the pot thoroughly after sautéing the onions.
Do not stir the orzo down into the liquid before pressure cooking; keeping it near the top helps prevent sticking.
For a thicker sauce, use less heavy cream or let the mixture simmer on the Sauté mode for a few extra minutes after pressure cooking.