In a large bowl, combine the mayonnaise, sweet chili sauce, sriracha, and lime juice to make the Bang Bang sauce. Mix well and set aside.
In another bowl, pour the buttermilk over the shrimp and let it marinate for about 15 minutes.
In a separate shallow dish, whisk together the flour, paprika, garlic powder, onion powder, salt, and black pepper.
Remove the shrimp from the buttermilk, allowing excess to drip off. Dredge each shrimp in the flour mixture, then dip back into the buttermilk, and finally coat with panko breadcrumbs.
In a large skillet, heat about 1 inch of vegetable oil over medium-high heat. Once hot, carefully add the shrimp in batches, frying for 2-3 minutes on each side or until golden brown and crispy. Remove and drain on paper towels.
Serve the crispy shrimp drizzled with the Bang Bang sauce or toss them in the sauce for an even coating.