Mix together garlic powder, salt and pepper.
Sprinkle on both sides of chicken breasts.
Place in Instant Pot and pour chicken broth in.
Close lid, close valve and cook for 15 minutes, high pressure. (If the chicken is still frozen, cook for 20 minutes)
Quick Release the pressure, use kitchen shears or forks and quickly chop or shred the chicken.
Break the linguine noodles in half and add to the Instant Pot.
Close lid & valve, and set the pressure cooker to cook for an additional 5 minutes, on high pressure.
While that is cooking, measure out your lemon juice and heavy cream.
Add 1 Tbsp of cornstarch to the lemon juice and mix well.
Once the timer beeps on the Instant Pot, quick release the pressure.
Add lemon juice mixture and heavy cream. Stir well.
Turn pressure cooker to Saute and let it cook another minute or two to thicken the sauce.
Dish onto plates or into bowls and top with Parmesan cheese.