Press the Sauté button on the Instant Pot. Add the olive oil and let it heat for a minute.
Add the cubed chicken breasts to the pot. Season with salt and pepper. Sauté until the chicken is browned on all sides, about 5 minutes.
Stir in the minced garlic and Italian seasoning. Cook for an additional 1-2 minutes until fragrant.
Pour in the chicken broth and scrape the bottom of the pot to prevent any burning (deglazing).
Add the fettuccine pasta, making sure it's submerged in the broth.
Secure the lid on the Instant Pot and set it to Manual or Pressure Cook for 4 minutes.
Once the cooking time is complete, perform a quick release of the pressure.
Carefully open the lid and stir in the heavy cream and grated Parmesan cheese until well combined. Adjust seasoning with more salt and pepper if needed.
Let the mixture sit for about 5 minutes, allowing it to thicken slightly.
Serve hot, garnished with freshly chopped parsley on top.