Cut the chicken breast, onion, potato, and carrot into bite-sized pieces.
Heat cooking oil in a pan and stir-fry the chicken breast.
Once the chicken breast turns golden, add the chopped vegetables and stir-fry together.
Add gochujang (Korean chili paste), soy sauce, minced garlic, sugar, and pepper, mixing and stir-frying well.
When the seasoning is evenly absorbed, add rice and stir-fry again.
Once everything is well mixed and the fried rice is finished, serve it in a bowl.