In a medium sized bowl prepare Lemon Garlic Marinade
Cut chicken into 1 inch pieces and toss well to coat. Let marinate at least 20 minutes, but preferably 24 hours.
Turn Instant Pot on and set to medium in saute mode
Once the indicator says HOT, add in onion and mushrooms. Let saute 2-3 minutes
Add in cubes of chicken and saute until the chicken begins to brown.
Pour uncooked penne noodles on top of chicken and mushroom mixture. Do NOT stir. Pour in 4 cups of chicken broth.
Cancel saute setting and set to High Pressure for 4 minutes.
Once the time is up and the Instant Pot beeps, allow to do a Natural Pressure Release for 4 additional minutes. Turn the sealing valve to open and finish with a Quick Release of any remaining pressure.
Remove lid, and stir penne to combine with the chicken and mushrooms. Pour in 1 cup cream and 2 cups of Parmesan Cheese and chopped parsley. Let sit on warm for 2-4 minutes to allow sauce to thicken, stirring often to avoid sticking.
Serve with additional chopped parsley and a sprinkle of shredded Parmesan on top.