Start by seasoning the thinly sliced chicken breasts. In a bowl, combine the garlic powder, onion powder, half of the kosher salt, and black pepper. Toss the chicken slices in the seasoning until evenly coated.
Set your Instant Pot to the “Sauté” function. Once hot, add the olive oil. Add the seasoned chicken to the pot and sauté for 4-5 minutes or until the chicken is browned but not fully cooked. Remove the chicken from the pot and set aside.
Pour in the chicken broth and use a wooden spoon to scrape up any browned bits from the bottom of the pot. This step is crucial for flavor and to prevent the burn warning.
Add the water to the pot, followed by the dry fettuccine pasta. Gently push the pasta down into the liquid, ensuring it is submerged but not stirred.
Place the browned chicken on top of the pasta without stirring. This will allow the chicken to finish cooking while the pasta is under pressure.
Seal the Instant Pot lid and set it to manual high pressure for 8 minutes. Once the cooking time is complete, perform a quick release of the pressure.
Carefully remove the lid and stir in the heavy cream, grated garlic, and Parmesan cheese. Mix until the cheese is melted and the sauce is creamy and smooth.
Taste and adjust the seasoning with the remaining kosher salt if needed. Serve immediately, garnished with additional Parmesan and chopped parsley if desired.