Slice chicken breast thinly into strips.
Finely mince the white tender part of the lemongrass stalk.
Heat oil in a wok, stir-fry garlic paste, minced lemongrass, and sliced green chilies for 1 minute.
Add chicken strips and stir-fry on high flame for 5 minutes until fully cooked.
Add soy sauce, sugar, and salt; toss well for 1 minute and serve.