Season chicken breasts on both sides with 1 tablespoon of Italian seasoning, 1 tablespoon of garlic powder, kosher salt, and pepper.
Turn pressure cooker to SAUTE- High. When display reads HOT, add olive oil to inner pot, then chicken breasts. Allow to sear and brown, about 3-4 minutes, then flip to the other side. Remove from pot and set aside.
Add butter to inner pot. When melted, add the mushrooms and season with garlic salt. Sauté until golden brown, then remove and set aside. Deglaze the pot with approximately 1/2 cup of chicken stock, using a spatula or wooden spoon to scrape up any bits from the bottom of the pot.
Pour the uncooked pasta into the pot, along with the remaining stock. Top with the chicken breasts. Lock lid into place, set release valve to SEAL, press CANCEL, then MANUAL. Set cooking time to 5 minutes.
Do a quick release when cooking time as elapsed. Remove chicken and chop to desired size. Return to pot, along with cream, parmesan, cream cheese, mushrooms and spinach. Stir together gently until cheese have melted and spinach has wilted.
Serve immediately.