Barbecue Chicken Sandwiches with Pickled Okra Slaw

Name: Barbecue Chicken Sandwiches with Pickled Okra Slaw
Ingredients: 1 1/2 pounds skinless, boneless chicken breasts (about 3 medium); 1/2 cup sliced pickled okra, plus 1/4 cup brine; 3 scallions (1 cut into thirds, 2 chopped); 2 tablespoons chopped fresh dill, plus 2 whole sprigs; 4 cups coleslaw mix (about 8 ounces); 3 tablespoons apple cider vinegar; 2 tablespoons extra-virgin olive oil; Kosher salt and freshly ground pepper; 4 whole-wheat sesame hamburger buns, split; 1/2 cup chili sauce (such as Heinz); 1 tablespoon molasses; 1 tablespoon yellow mustard