Cut the chicken into bite-sized chunks and soak them in buttermilk for at least 30 minutes.
Mix flour, cornstarch, garlic powder, paprika, salt, and black pepper in a bowl.
Heat oil in a deep pan until hot enough for frying.
Dredge chicken pieces in the flour mixture, making sure each piece is well coated.
Fry the chicken until golden and crispy, about 4 to 6 minutes per batch. Place on paper towels to drain excess oil.
In a small bowl, whisk together mayonnaise, sweet chili sauce, sriracha, and honey.
Toss the crispy chicken in the sauce until fully coated.
Top with chopped green onions and serve hot.