Bring large pot of salted water to boil. Cook pasta until al dente, according to package directions. Drain.
In large bowl, toss together pasta, chicken, broccoli, celery, onions, cranberries and pecans.
In a small bowl, whisk together mayonnaise, sour cream, sugar, Dijon mustard, Italian seasoning, garlic powder and black pepper until well combined. Add salt to taste.
Pour dressing over pasta mixture and toss with a wooden spoon until pasta is evenly coated with dressing. Add more salt and pepper to taste.
Enjoy now or store covered in refrigerator until ready to serve.
Mayonnaise brands may vary in saltiness, so we like to add salt to taste after mixing dressing ingredients.Lite mayonnaise and light sour cream may be substituted for the full fat varieties. Calories and fat in nutrition information are for regular mayonnaise and sour cream.