Slice each chicken breast in half horizontally to create four thin pieces.

In a shallow dish, mix together the flour, salt, black pepper, garlic powder, onion powder, and dried dill. In another bowl, whisk together the eggs and milk. Place the panko breadcrumbs in a separate dish.

Dip each piece of chicken into the flour mixture, then into the egg mixture, and finally press into the panko breadcrumbs.

Heat vegetable oil in a skillet over medium-high heat. Fry each piece of chicken for about 4–5 minutes on each side until golden brown.

In a small bowl, combine mayonnaise with fresh dill and lemon juice to create the dill mayo.

Lightly toast the brioche buns.

Spread dill mayo on both sides of each bun, layer with shredded lettuce, fried chicken, and dill pickle slices.

Serve the sandwiches warm.