Bring large saucepan of salted water to a boil. Add pasta from salad mix to water. Reduce heat to medium. Boil gently 12 minutes, stirring occasionally. Drain; rinse with cold water and shake to remove excess moisture.
Meanwhile, in very large bowl, combine seasoning mix from salad mix, sour cream, mayonnaise, milk and salt; blend well. Add chicken, celery, sun-dried tomatoes, onions and bell pepper.
Add pasta to chicken mixture; stir to combine. Cover; refrigerate at least 1 hour to chill, or until serving time.
Just before serving, sprinkle contents of topping packets from salad mix over salad.