Place the chicken, celery, scallion, cranberries, walnuts, and parsley in a large bowl, set aside.
In a small bowl, whisk together the mayo, garlic, vinegar, oregano, mustard, worcestershire sauce, sugar, salt, and pepper. Add the dressing to the chicken mixture, only add about half and toss to coat. Add more if needed.
Notes
Use any leftover dressing as a regular salad dressing, it's amazing! (Great for potato salad too!)