The 30-year-old Chico, who came out of retirement only three years ago, threatened to pull away from the field with a solid start until she stumbled with a double-bogey on the 16th and a triple-bogey on the 18th that enabled at least four players to get a crack at the title.
Two members of the Taiwanese national team will be shooting it out with Chico, the 1988 champion who had a 36-hole aggregate of 156, in today’s final pairing.
Shih Huei Jun remained in second place at 158 after an 80 while Hung Chin Huei jumped to solo third at 159 with her round of 79.
Aileen Yao and jungolf standout Jayvee Agojo both turned in 81s to keep within striking distance of the leader at 160 while club bet Heidi Chua bounced back with the day’s best score of 76 to join Carmelette Villaroman-Calimag (78) at 161.
Lucy Landicho-Sales, whose first round effort of 76 gave her the solo lead, dropped five strokes on the first five holes and failed to recover her bearing, limping with an 88 and a 164.
"Umpisa pa lang masama na, hindi na tumigil ang sabog," said Sales.
In contrast, Walker had a good start.
Birdies on the fifth and seventh holes gave Walker a two-under card although she blew it when she double-bogeyed the par-3 8th. But the rest of the field likewise fell prey to the demanding conditions of the layout and Walker surged ahead despite a bogey on No. 10 as she made four straight pars to the 15th.
"My game just fell apart in the closing holes. I’m just so lucky to be the leader," said Chico, who is aiming to end a five-year victory drought. Her last win came in the 1995 Southern Ladies.