Soak the peeled and deveined shrimp in buttermilk for at least 30 minutes in the refrigerator.
Combine all-purpose flour with paprika, garlic powder, onion powder, cayenne pepper, salt, and black pepper.
Remove the shrimp from the buttermilk and dredge them in the seasoned flour mixture.
Dip each floured shrimp back into the buttermilk and then roll them in panko breadcrumbs.
Heat oil in a skillet and fry the shrimp until golden brown, about 2-3 minutes per side.
Whisk together mayonnaise, sweet chili sauce, and sriracha. Assemble tacos with cabbage, shrimp, sauce, and avocado.