In 3 1/2- to 4-quart slow cooker, place chicken and onion. In small bowl, mix broth and paprika; pour over chicken. Sprinkle with salt.
Cover; cook on Low heat setting 7 to 8 hours.
About 20 minutes before serving, cook and drain noodles as directed on package.
Remove chicken and onion from cooker, using slotted spoon. Place on serving platter; cover to keep warm. In small bowl, mix cornstarch and water; stir into juices in cooker. Increase heat setting to High. Cover; cook about 10 minutes or until thickened. Stir in potato topper. Pour sauce over chicken. Serve over noodles.