I made mine with gluten free bread crumbs, and baked them, but feel free to use what you like, have on hand, or have the time and energy for — frozen
chicken fingers (yup, the is what mom usually did), homemade fried or baked breaded
chicken tenderloins, really even boneless,
skinless breasts can be used if you want to keep it lighter, but it doesn't absorb the flavor and help to thicken the sauce quite as well.