In a medium bowl, combine soy sauce, honey, hoisin sauce, balsamic glaze, Thai sweet red chili sauce, sesame oil, garlic and onion. Pour sauce over chicken, cover with the lid and cook on low for 3 to 4 hours or high for 1-1/2 to 2 hours.
To thicken the sauce, whisk together cornstarch and water in a small bowl and stir into slow cooker. Turn heat to high and allow the sauce to cook and thicken for 15-20 minutes.
Serve hot with sauce over cooked rice or noodles. Sprinkle with green onions and sesame seeds, if desired
*Use low sodium soy sauce if possible.
Due to the lower heating element in older slow cookers, the sauce may not thicken in the slow cooker. If that is the case, spoon out all the sauce from the slow cooker into a small saucepan and bring to a boil on high heat until it thickens up. Pour sauce over chicken and stir to combine.