Marinate the chicken breasts in buttermilk for at least 30 minutes or overnight in the refrigerator for enhanced flavor.
In a bowl, combine flour, garlic powder, onion powder, paprika, cayenne pepper, salt, and pepper.
Remove chicken from buttermilk, letting excess drip off, then dredge each breast in the flour mixture until well coated.
Heat about ½ inch of cooking oil in a large skillet over medium-high heat until shimmering.
Fry the coated chicken breasts in the hot oil for 6-7 minutes per side until golden brown and internal temperature reaches 165°F (75°C).
Remove chicken and drain on paper towel-lined plate, then toss while hot in buffalo sauce to coat evenly.
Prepare the ranch slaw by combining shredded cabbage, shredded carrots, and ranch dressing; toss to coat.
Optionally toast the burger buns in the skillet until golden brown.
Assemble sandwiches by placing buffalo chicken on bottom bun, topping with ranch slaw, then adding the top bun.
Serve immediately with sliced pickles if desired.