Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain, and set aside.
In a medium bowl, whisk together coleslaw dressing, mayonnaise, and creamy salad dressing.
In a large bowl, combine pasta, chicken, green grapes, red grapes, water chestnuts, celery, and green onions. Stir in dressing, and mix well. Place the salad in the refrigerator to marinate for 2 hours, or overnight. Mix in cashews and dried cranberries just before serving. Serve cold.
