Combine 1/2 cup Hellmann's® or Best Foods® Real Mayonnaise with Cajun spice with wire whisk in small bowl. Cover and refrigerate 30 minutes.
Combine remaining 1/2 cup Mayonnaise, mustard, horseradish, Worcestershire sauce, lemon juice and parsley with wire whisk in medium bowl. Season, if desired, with salt and pepper. Cover and refrigerate until ready to use.
Season chicken, if desired, with salt and pepper. Brush chicken with Cajun mayonnaise. Arrange chicken on baking sheet and broil, turning once, 10 minutes or until golden and chicken is thoroughly cooked. Serve with Creole mustard sauce.