In a mixing bowl, combine shredded chicken and BBQ sauce.
Spread butter on one side of each slice of bread.
Place four slices of bread, buttered side down, on a griddle or skillet over medium heat.
Top the bread with 1/4 of the cheese, followed by the BBQ chicken, and then another 1/4 of the cheese.
Cover with another slice of bread, buttered side up, and cook until the bottom is golden brown and the cheese begins to melt, about 3-4 minutes.
Carefully flip the sandwich and cook until the other side is golden brown and the cheese is fully melted, about another 3-4 minutes.
Once cooked, remove sandwiches from the skillet and let them sit for a minute before slicing.
Serve hot with optional pickles or jalapeƱos on the side.