Cut the chicken breast into bite-sized pieces.
Slice the onion, cabbage, and green onions.
Mix gochujang, red pepper powder, soy sauce, minced garlic, erythritol, pepper, and sesame oil to make the sauce.
Add the sauce to the chicken breast and mix well.
Place the chicken breast and vegetables in a pan and stir-fry.
Cook over medium heat until the chicken breast is fully cooked.