Combine first 3 ingredients in a bowl; toss well to coat. Combine ketchup and next 8 ingredients (Ketchup through garlic powder) in a medium saucepan; bring to a boil. REduce heat; simmer 5 minutes or until mixture begins to thicken. Stir in chicken, and cook 4 minutes or until roasted chicken is thoroughly heated. Top each toasted bread slice with 1/2 cup chicken and 1/2 cup coleslaw mixture.