Cut chicken into bite size pieces and set aside.
Add olive oil and onion to an instant pot and turn on to saute setting.
Saute onion for 2-3 minutes or until tender then add the garlic, chicken pieces, italian seasoning, salt & pepper.
Saute for another 3-4 minutes.
Add the pasta, marinara sauce and water; stir to combine.
Press the cancel button, close and lock the lid and seal the valve.
Select the manual setting, adjust the pressure to high and set time to 5 minutes.
When finished cooking, quick-release pressure according to the manufacturer’s directions.
Open the lid, sprinkle both kinds of cheese, close the lid and let the cheese melt for one minute.
