The third round on Saturday saw Natthakritta sign for an eight-under-par 64 at the par-72 Siam Country Club Pattaya Old Course in Chonburi.
Her bogey-free card gave the 20-year-old home pro a total of 196.
Natthakritta has a four-shot cushion over her closest rival, compatriot Atthaya Thitikul, who moved into second place after also shooting eight-under for a total of 200.
The pair have been grouped together for the fourth round, meaning Thai fans can watch their blow-by-blow battle to become the second home win of the tournament after Ariya Jutanugarn in 2021.
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