Clean the chicken thoroughly.
Cut potatoes, carrots, and onions into bite-sized pieces.
Heat cooking oil in a pan and stir-fry the chicken.
When the chicken is half-cooked, add potatoes and carrots and stir-fry together.
Add soy sauce, sugar, minced garlic, pepper, and water, then bring to a boil.
Add onions and green onions.
Simmer over medium heat until the sauce slightly thickens.
Finish with sesame oil to taste, if desired.