In a bowl, combine the fish sauce, garlic, curry powder, salt and 1 ½ teaspoons sugar. Add the chicken to coat.
In a hot skillet, sautee the lemongrass with the onion and chilies in a little oil until fragrant.
Add the palm sugar and cook to caramelize, then add the water to stop it from burning. Set aside in a bowl.
Add a little more oil to the skillet, then caramelize the chicken until cooked through. Add back the sauce and simmer until the chicken is cooked through and the sauce is thickened