Chop off both ends of the green beans (or just break them off with your hands), and wash thoroughly.
Cut the chicken into small pieces, and marinade with the chicken broth mix, rice wine, soy sauce, 1 teaspoon of the corn starch, and 1 teaspoon of the sugar.
Take the remaining corn starch, and mix with 2-3 teaspoons of water. Set aside for later use.
Heat the wok (or pan) with cooking oil, then add the garlic. Once the garlic starts to turn a little brown, add the chicken and stir-fry until it is almost all cooked.
Once the chicken is ready, add the green beans and stir-fry. Add 1/2 cup of water, sugar, and oyster sauce. Cover the wok (or pan) with a lid until the green beans are cooked while the sauce comes to a boil.
Grab the corn starch mixture that was prepared from Step #3, and make sure to mix it again, as the corn starch may have settled to the bottom. Add the mixture into the wok (or pan). This will thicken the sauce.