Place chicken breasts in the bottom of a slow cooker.
In a medium bowl, whisk together hot sauce, chicken broth, garlic powder, onion powder, and black pepper.
Pour the mixture over the chicken.
Cover and cook on low for 4 to 5 hours or high for 1.5 to 2.5 hours, until the chicken is cooked through.
Remove the chicken and shred it with two forks.
In a small bowl, stir together the cornstarch and water to create a slurry.
Add the slurry to the slow cooker and whisk to combine with the remaining liquid.
Return the shredded chicken to the slow cooker and stir to coat with the sauce.
Cover and cook on high for 30 additional minutes, or until the sauce has thickened slightly.
Serve hot, topped with green onions and blue cheese if desired.