In a large bowl, combine the buttermilk, mayonnaise, 1 tablespoon of the hot sauce, and salt and cayenne pepper to taste. Whisk until fully combined, then add the chicken to the bowl and toss to coat. Cover and let marinate in refrigerator for at least 30 minutes and up to overnight.
Preheat oven to 425℉. Line a baking sheet with parchment paper or aluminum foil.
Arrange the sweet potato rounds and shredded Brussels sprouts on the sheet pan, drizzle with olive oil and roast 20 minutes.
In another bowl, combine the Corn Flakes with salt and cayenne pepper to taste. Remove the chicken from the marinade and dredge in the crumbs, pressing gently so they adhere.
Remove the sheet pan with sweet potatoes from the oven and add the chicken to the pan. Return the pan to the oven and bake for 20 minutes or until browned and crispy. Turn chicken over and bake 10 minutes longer or until cooked through.
Make Hot Honey Butter: Combine butter, honey, hot sauce, cayenne pepper and salt in a small saucepan. Cook and stir over medium heat until honey is dissolved and mixture is completely combined.
Drizzle Hot Honey Butter over chicken and potatoes and Brussels sprouts.