Poach chicken breasts in simmering water for 15-20 minutes until the internal temperature reaches 165°F (74°C).
Remove chicken from liquid, allow to cool slightly, and shred using two forks.
In a large mixing bowl, combine Greek yogurt, hot sauce, light mayonnaise, garlic powder, salt, and pepper.
Add the shredded chicken, celery, and red onion to the bowl and toss until thoroughly coated in the dressing.
Fold in the blue cheese crumbles gently to maintain texture.
Serve immediately over mixed greens or refrigerate for 30 minutes to allow flavors to meld.