Heat oven to 375 degrees. Spray 8 inch square (1 1/2 quart) baking dish with nonstick spray.
Place 1 chicken breast between 2 pieces of plastic wrap or waxed paper. Working from center, gently pound chicken with rolling pin or flat side of meat mallet until about 1/4 inch thick. Repeat with remaining chicken pieces, making four cutlets.
Spread each cutlet with 1/2 teaspoon mustard; sprinkle each with 1 teaspoon chives. Cut ham and cheese slices to fit chicken cutlets. Roll up, tucking ends inside.
In a shallow bowl, combine egg white and water; beat slightly. Place cornflake crumbs in shallow dish. Coat chicken rolls with egg white mixture; roll in cornflake crumbs. Place in spray-coated dish. Sprinkle with paprika. Bake at 375 degrees for 25-30 minutes or until chicken is fork tender and juices are clear.