Place lemongrass, shallot, chili, and garlic in a mortar and gently pound with a pestle until a paste forms.
Add sugar, combined sauces and oil, and stir to combine. Place in a glass or ceramic bowl and add the chicken. Stir to combine. Cover with plastic wrap and place in fridge for 1 hour to mature the flavours.
Thread the chicken evenly among the skewers.
Preheat a char-grill pan on high.
Add chicken and cook for 2-3 minutes each side or until cooked through.
Transfer to a platter, sprinkle with green onions and serve immediately with steamed jasmine rice.