In a bowl, whisk together soy sauce, brown sugar, honey, garlic, ginger, gochujang, and sesame oil. Set aside.
Pat chicken dry and season lightly with salt and black pepper.
Heat olive oil in a skillet or grill pan over medium-high heat.
Cook chicken for 5–7 minutes per side until fully cooked.
Reduce heat slightly and brush or toss chicken with Korean BBQ sauce.
Cook for another 1–2 minutes until sauce thickens slightly and coats the chicken.
Lightly toast brioche buns if desired.
Spread mayo or spicy mayo onto buns.
Add Korean BBQ chicken, coleslaw, pickles, and green onions.
Top with remaining bun halves and serve warm.