Skillet Caprese Chicken Casserole

Name: Skillet Caprese Chicken Casserole
Ingredients: 8 ounces whole-wheat penne or rotini; 1 pound boneless, skinless chicken breasts, trimmed and cut into bite-size pieces; 1 pint grape tomatoes, halved; ½ cup chopped fresh basil, divided; 2 ¼ cups low-sodium chicken broth; 1 cup reduced-fat milk; ½ cup reduced-fat sour cream; 3 tablespoons all-purpose flour; 1 teaspoon onion powder; 1 teaspoon dry mustard; ¼ teaspoon salt; ¼ teaspoon ground pepper; 1 cup shredded mozzarella cheese; Good-quality balsamic vinegar (optional)