By Lerpong Amsa-ngiam
The 25-year-old cyclist, who also won the first stages of this tournament in 2015 and 2017, stole the show on day two, which featured a distance of 117.45km from Kaen Nakhon Lake to Ban Fang district in Khon Kaen.
Nguyen also won the Best Asean Rider title while the Best Sprinter category went to Nina Kessler of the Netherlands.
In the overall event, 2016 Olympic team time trial gold medalist Olga Zabelinskaya of Russia held onto to her pink jersey after timing a total 4:08.18 hours.
Russia National Team were leading in the team overall, clocking a total 11:33.42 hours while Vietnam National Team held the top spot of the Best Asean Team with 11:36.08 hours.