Whisk together the fish sauce, sriracha, rice vinegar, ginger and brown sugar.
In a bowl, place your cubed chicken and toss with marinade.
Let marinade for about an hour.
Skewer the meat onto skewers and reserve the marinade.
Heat your BBQ up to about medium heat.
Put the reserved marinade in a small saucepan, bring to a boil, reduce the heat and let simmer until reduced by about 1/2.
Grill your chicken on the BBQ until cooked. about 8-10 minutes.
Brush the chicken when finished with the reduced glaze.