The 30-year-old finally cut off her time on court after needing more than three hours in each of the two previous rounds, underlining her supremacy over the South Korean for the fourth time after one hour and 23 minutes.
"Each player has different styles. Some has the game that suits mine but some doesn't. I'm just happy that I'm still physically OK," said the former national player Nudnida.
Nudnida whose run was halted seven days ago in the semi-final by Patcharin Cheapchandej next faces Australian teenager Michaela Haet who advanced following a 6-1 6-1 win over Alicia Smith also from the same country.
"I have a tough opponent waiting for me in the semi-finals. She has powerful groundstrokes. I have to play solid game against her," Nudnida said.
Chihiro Muramatsu
Circuit 1 winner Patcharin meanwhile saw her nine match winning streak come to an end by Japanese lefthander Chihiro Muramatsu, losing 4-6 5-7. Next up for the Japanese teen is top seed Harriet Dart of the UK, a 7-5 6-2 winner over Sara Tomic of Australia.