In a medium bowl, combine the chicken and barbecue sauce. Mix well and set aside.
Place the bread slices on a flat work surface. Spread 1 tablespoon of butter evenly over one side of each slice of bread.
Warm a skillet over medium heat for 3 to 5 minutes. Layer each sandwich as follows: Slice of bread, butter side down, ½ cup shredded American cheese (or 2 slices), ½ of the chicken mixture, 3 pickle slices, ½ cup shredded American cheese (or 2 slices) and slice of bread, butter side up.
Place sandwiches onto the hot skillet. Cook on each side for about 3 to 4 minutes, or until the bottom layer of cheese begins to melt around the edges. Cut in half and serve!