If using precooked chicken (leftovers or rotisserie are great) make sure it is diced into bite size pieces and put it into your pressure cooker.If using fresh chicken (make sure pieces are diced into small bite size pieces) set pot to saute with 1 tbsp olive oil and cook until outsides are no longer pink. Then turn pot off.
Add mixed vegetables and garlic salt into your pot with your chicken. Sprinkle uncooked noodles noodles on the top.
In a bowl whisk together your broth and cream of chicken soup so it is smooth/well combined. Dump this into your Instant Pot and gently submerge noodles into liquid below.
Close your lid and steam valve and set to high pressure for 2 minutes.
Do a quick release and stir contents. Set your pot to saute again.
In a bowl whisk together half and half and cornstarch until smooth, pour this mixture into your pot once contents are bubbling.
Stir, will thicken quickly. Stir in cheese and allow to melt. Turn pot off and pour contents into a serving dish so it doesn't continue to cook and noodles get too soft.