GRILL THE CHICKEN. Heat a gas grill to medium. Remove chicken breast from marinade (discard marinade) and place on the grill and cook, covered, until grill marks form on the first side, about 3 minutes. Using tongs, move the pieces on a slight angle and continue cooking, covered, for 2 minutes to form crosshatch marks. Flip the pieces over and cook for 3 to 4 more minutes, or until the chicken breast are cooked through. Transfer to a cutting board, let rest for a couple of minutes, and chop very fine!