Spread one side of each slice of bread with margarine, and place a bread slice, margarine-side down, into a nonstick skillet over medium heat.
Place a slice of Swiss cheese, the cooked chicken breast, a layer of barbecue sauce, the ham slices, and the remaining Swiss cheese slice onto the bread slice in the skillet. Top the sandwich with the other bread slice, margarine-side up.
Gently fry the sandwich, flipping once, until the cheese is melted and gooey, and the bread is golden brown on both sides, about 5 minutes per side.
