Lt-General Thitithan Suksri (middle) and all winners.
The world No 9, raised his game and intensified his attacks after losing the opener 16-21, to subdue the world No 16 21-13 21-12 in the next two games to win the Super 300 event.
Ng’s last win was in the Malaysian Masters, then classified as a Grand Prix event in 2017. He earned US$12,750 as the winner’s cheque.
Nishimoto has yet to win a title, having lost six finals. He will return to Japan with a runner's-up cheque of US$6,460.
On the women’s side, world No 3 Akana Yamaguchi of Japan scored her first victory over South Korean teenager An Se Young after a tough grind, winning 21-14 22-20 in 48 minutes. It was her first win over the 17-year-old Korean after losing their previous encounters at the Korea Masters and French Open last year.
Former world No 1 Yamaguchi has won a total of six BWF World Tour titles. She earned US$12,750 for her victory in Bangkok. An, No 9 in the world, received US$6,460.