Stir together shredded chicken and bbq sauce in a bowl. Spread butter on one side of each slice of the bread. Layer one slice of cheese, then a scoop of bbq chicken and then another slice of cheese between 2 slices of bread (the unbuttered side).
Place bread buttered side down in a skillet over medium heat. Cover with a lid or foil and let cook for 3-4 minutes or until golden. Flip sandwich, reduce heat to medium-low, and cook for 2-3 minutes more or until bread is toasty and cheese has melted. Remove from pan and allow to cool slightly before cutting in half.
Recipe by Red Kitchenette at http://www.redkitchenette.com/2015/01/09/5-ingredients-or-less-bbq-chicken-grilled-cheese/