In a bowl, marinate the chicken thighs in buttermilk for at least 30 minutes.
In another bowl, mix flour, cornstarch, salt, pepper, garlic powder, and paprika.
Dredge each chicken thigh in the flour mixture, shaking off excess.
Heat oil in a deep skillet to 350°F (175°C). Fry chicken for 6-7 minutes per side until golden brown and crispy.
In a separate bowl, mix mayonnaise, sweet chili sauce, Sriracha, honey, and lime juice to make the sauce.
Drizzle the sauce over the fried chicken and garnish with chopped green onions.
Serve hot with your favorite side dish.