Olympic champion Chen, favourite for the title, went down 21-17 21-19 in her first ever defeat to her 24-year-old opponent in four meetings.
Home girl Kim next faces Goh Jin Wei, who leads their head-to-head 2-1. Goh booked her quarterfinal spot with a win over another Korean Lee Se Yeon.
Men’s singles sixth seed and YONEX All England Open 2022 runner-up Lakshya Sen’s campaign also ended with a surprise 22-20 21-9 loss to Shesar Hiren Rhustavito. The Indonesian world No.24 thus matches his performance from the previous edition in 2019.
Son Wanho qualified for his first quarterfinal since the Syed Modi International in 2019. The 33-year-old is on a three-game winning run against his last eight opponent Kidambi Srikanth. His last loss to the Indian came in 2017 at the Australia Open.
Ratchanok Intanon meets fellow Thai Pornpawee Chochuwong for the fourth time in her career. She lost their most recent duel at the HSBC BWF World Tour Finals in Bangkok in January last year.