1. Pound chicken breasts to even 1/2-inch thickness, place in shallow dish, cover with pickle juice, and refrigerate 2+ hours or overnight.
2. Set up breading station: Dish 1: mix flour, half the garlic powder, salt, and pepper. Dish 2: whisk eggs and dijon mustard. Dish 3: combine panko, chopped pickles, parmesan, remaining garlic powder, dried dill, black pepper, and cayenne.
3. Remove chicken from brine, pat dry. Dredge in flour mixture, dip in egg mixture, then press firmly into panko-pickle mixture. Let rest 5-10 minutes on wire rack.
4. Heat oil in large skillet over medium heat. Cook chicken 4-5 minutes per side until golden brown and internal temperature reaches 165°F.
5. Transfer to wire rack and rest 5 minutes before serving. Garnish with fresh dill, pickle slices, and additional parmesan if desired.