Stir together mayonnaise, sweet chili sauce, and Sriracha sauce in a small bowl. Refrigerate until needed.
In a medium bowl, whisk together buttermilk, flour, cornstarch, egg, hot sauce, salt, pepper, and garlic powder.
Place Panko crumbs in a shallow dish.
Cut chicken into 1-inch pieces. Dip in buttermilk mixture and then dredge them in the Panko crumbs.
Heat 1-inch of oil in a Dutch oven to 360 degrees F.
Fry chicken in batches for 2 to 3 minutes, flipping over to brown both sides. Transfer to a paper towel-lined plate.
Drizzle with reserved sauce and serve.