Cut the chicken breast into bite-sized pieces.
Slice vegetables such as onion, carrot, and cabbage.
Mix chicken breast with gochujang, soy sauce, minced garlic, chili powder, sugar, pepper, and sesame oil in a bowl to season.
Add cooking oil to a pan and stir-fry the seasoned chicken breast.
When the chicken breast is halfway cooked, add the vegetables and stir-fry together.
Cook until all the ingredients are done, then serve.