Season chicken with salt, pepper and garlic powder.
Press the Sauté function on the Instant Pot and add the olive oil to the pot.
Place chicken in the Instant Pot and allow to sear on each side for 2 minutes, or until golden brown. Remove from Instant Pot and set aside.
Melt butter in Instant Pot and stir in the onions and garlic. Add lemon juice to deglaze pan. Cook for 1 minute then add Italian seasoning, lemon zest, and chicken broth.
Place the chicken back into the Instant Pot, lock the lid, and turn the valve to SEAL.
Select the Manual or Pressure Cook button and adjust the timer to 7 minutes.
Allow the pot to come to pressure (about 5-10 minutes) and start counting down.
When done, allow to naturally release for 2-3 minutes then push the valve to RELEASE and remove the lid.
Optional: Make a cornstarch slurry using 1 teaspoon cornstarch whisked with 2 teaspoons cold water and stir into the pot. Press SAUTÉ and allow to bubble and thicken.
Sprinkle with chopped parsley and serve hot with your favorite sides. Spoon sauce over chicken and garnish with lemon slices if desired.
