The world No 15 was engaged in a neck-and-neck duel with the old foe before she narrowly won the match in 69 minutes with a repertoire of shots. She also snapped the three losing streaks to the Malaysian and reduced the lifetime record against the rival to 2-3.
Hailing from Phuket the 26-year-old Nitchaon also won her first World Grand Prix title here in 2013. Last year she also reached the final but lost to He Bingjiao of China 11-21 18-21.
Thailand also won the women's doubles after second seeded Jongkolphan Kititharakul and Rawinda Prajongjai beat Japanese Akane Araki and Aoi Matsuda 21-19 21-6.