Cook noodles according to package directions. Drain and rinse under cold water to cool.
Meanwhile, whisk together mayonnaise, yogurt, hot sauce and vinegar in a large bowl. Stir in the noodles, chicken, scallion whites, celery, carrot and blue cheese. Garnish with scallion greens and serve.
To make ahead: Refrigerate for up to 1 day.
1 starch, 1/2 fat, 1/2 high-fat protein, 1/2 lean protein