Prepare the Bang Bang sauce by whisking together the mayonnaise, sweet chili sauce, Sriracha, and honey in a medium bowl. Set aside.
In a shallow bowl, whisk the buttermilk and hot sauce. Submerge the chicken cutlets and allow to marinate for 10 minutes.
In a separate wide container, whisk together the flour, cornstarch, paprika, garlic powder, onion powder, cayenne, salt, and pepper.
Heat 1/2 inch of oil in a heavy-bottomed skillet over medium-high heat until it reaches 350°F (175°C).
Remove chicken from buttermilk, allowing excess to drip off, then dredge thoroughly in the flour mixture, pressing firmly to create a craggy crust.
Fry the chicken for 4 to 5 minutes per side until the exterior is golden brown and the internal temperature reaches 165°F (74°C). Drain on a wire rack.
In a small bowl, toss the shredded cabbage with apple cider vinegar and a pinch of salt.
Lightly toast the brioche buns. Coat each fried chicken piece in the Bang Bang sauce.
Assemble by placing the sauced chicken on the bottom bun, topping with the slaw, and finishing with the top bun.