Cut the chicken into bite-sized pieces.
Dice the onion, carrot, and potato.
Heat cooking oil in a pan and stir-fry the chicken.
Add the vegetables and stir-fry together.
Add soy sauce, sugar, minced garlic, pepper, and water, then bring to a boil.
Simmer over medium heat until the ingredients are cooked through.
When the sauce has reduced, turn off the heat and transfer to a serving dish.