Submerge the chicken breasts in pickle brine and refrigerate for 2 hours.
Combine flour, powdered sugar, paprika, garlic powder, and black pepper in a shallow dish.
Remove chicken from brine, pat dry, and dredge each piece in the seasoned flour mixture until fully coated.
Heat peanut oil in a deep skillet to 350°F / 175°C and fry chicken for 7 to 8 minutes per side until golden brown and internal temperature reaches 165°F / 74°C.
Transfer chicken to a wire rack and rest for 5 minutes.
Place each chicken breast on a toasted brioche bun and top with 2 pickle slices before serving.