Cut the chicken breast into bite-sized pieces.
Julienne the onion and bell pepper.
Heat a little oil in a pan and stir-fry the chicken breast.
When the chicken is halfway cooked, add the vegetables and continue stir-frying.
Add the seasoning sauce made with gochujang, soy sauce, and minced garlic, and mix everything well.
When all the ingredients are cooked through, plate and serve.