Rinse and cook rice with water. When cooked, transfer rice to either a wooden or glass bowl and add in oyster sauce and sugar to mix. Set aside to cool before mixing in vinegar.
Mix well chicken with marinade and set aside to marinate for 20 minutes. Heat up a grill pan and brush on some sesame seed oil. Grill chicken till golden brown and cooked. Let it rest before slicing into thin slices.
Roll rice into oblong shaped rolls and drape on the grilled chicken slices. Garnish with wrapping the nori strip across the center of the sushi roll. Serve.
Tip : Do not use aluminium utensils when mixing sushi rice as this type of metal will retain heat differently and give the rice a metallic taste.