Cut the chicken into bite-sized pieces.
Chop the onion, potato, and green onion into edible sizes.
Heat vegetable oil in a pan and stir-fry the chicken.
Add the onion, potato, and green onion and stir-fry together.
Add gochujang (Korean chili paste), chili powder, soy sauce, garlic, and sugar to season.
Pour in water and boil until the ingredients are cooked.
Turn the heat up and reduce the sauce until thickened to finish.