In a large bowl, combine chicken thighs with buttermilk, salt, and white pepper. Cover and refrigerate for 30 minutes to 2 hours.

In a wide bowl, whisk together self-rising flour, onion powder, garlic powder, paprika, and Tony's seasoning until combined.

Fill a Dutch oven with 1½ inches of vegetable oil and heat to 350°F (175°C).

Dredge marinated chicken in the flour mixture, then fry in hot oil for 6-7 minutes each side until golden brown. Drain excess oil on a wire rack.

In a small saucepan, combine bourbon and sweet chili sauce, simmering for 5-7 minutes until thickened. Let cool.

Whisk eggs with a splash of milk. Dip brioche slices in the egg mixture and cook in a skillet with butter until golden brown.

Assemble the sandwich by placing fried chicken between two slices of French toast, drizzle with the bourbon sweet chili sauce, then serve warm.