BBQ Chicken Sandwiches with Napa Slaw

Name: BBQ Chicken Sandwiches with Napa Slaw
Ingredients: 1/2 cup plus 1 tablespoon ketchup; 1/3 cup unsulphured molasses; 1/4 cup yellow mustard; 1 tablespoon cider vinegar; 1 teaspoon Worcestershire sauce; 1 teaspoon soy sauce; 4 large skinless, boneless chicken breast halves, trimmed; 4 hamburger buns, split; 1/3 cup mayonnaise; 2 tablespoons cider vinegar; 2 teaspoons sugar; 1/2 medium onion, finely chopped; 1/4 cup minced chives; 1 medium head of napa cabbage, quartered lengthwise and thinly sliced crosswise; Salt and freshly ground pepper