Chicken Reuben

Ingredients:
Reserved roasted chicken breast halves from Crispy Mustard Chicken with Carrots, deboned
8 slices rye bread
4 ounces sliced Swiss cheese
1 pound (1 jar or package) sauerkraut, drained and squeezed dry (not rinsed)
1/3 cup light mayonnaise
2 tablespoons ketchup