Marinate the Chicken In a bowl or zip-top bag, whisk together the pickle juice, milk, and egg. Add chicken and marinate for at least 30 minutes (up to overnight for best flavor).
Make the Breading In a shallow bowl, mix flour, powdered sugar, and seasonings until well combined.
Dredge and Coat Remove chicken from marinade. Dredge in the seasoned flour, pressing in firmly. For extra crispy chicken, dip again in the marinade and re-dredge.
Fry to Golden Perfection Heat oil in a deep skillet or heavy pan to 350°F. Fry each piece of chicken for 3–4 minutes per side until golden brown and fully cooked (internal temp: 165°F). Let drain on a wire rack or paper towel.
Toast and Stack Lightly butter your buns and toast until golden. Build your sandwich: Bottom bun → pickles → fried chicken → cheese → tomato → lettuce → optional sauce → top bun