Nirat was on his way to another record performance until bogeys at 17 and 18. Had he parred both of those holes, he would have matched David Howells 54-hole record from last year, which was also equaled the European Tour record for lowest three-round total.
On Thursday, he established a new course record with an 11-under-par 61. One day later, he tied Howell's 36-hole mark, but Nirat is on pace to avoiding Howell's fate from 2006.
Howell lost the tournament last year to Johan Edfors by five shots, but Nirat is five ahead with one round to go before his first visit to the winners circle.
Nirat's closest pursuers are Miles Tunnicliff, who fired a 65 on Saturday, and Taichi Teshima, who posted a 6-under 66 in round three. That pair is knotted at 16-under-par 200.
Rafael Echenique, who began the third round tied for second place, carded a 4-under 68 and is alone in fourth place at minus-15.
These players are going to need some type of slip from Nirat. That has not been evident so far this week as Nirat has tallied an eagle, 23 birdies and four bogeys.
Nirat parred his first three holes on Saturday, then broke into red figures with a birdie at the par-4 fourth, a hole he bogeyed on Friday, but birdied on Thursday. Nirat parred his next three and his lead dropped to four, but he closed his opening nine with back-to-back birdies at eight, a chip-in, nonetheless, and nine to push his advantage to six.
Teshima moved up the leaderboard to threaten Nirat a bit, but the Thailand native responded. He rattled off three consecutive birdies from 11, including a pair of 15-footers, and found himself seven shots clear of the field.
Trouble loomed for Nirat as he three-putted No. 14 for only his second bogey of the tournament. He answered with a birdie at the par-5 16th, a hole he has played in 4 under for the week.
He was now 23 under par and on pace to match Howell's record, but poor drives at 17 and 18 led to bogeys and eliminated any chance to put his name in the tournament record book again. Instead, Nirat will walk into Sunday's final round with a five-shot lead.
Wen-teh Lu carded a 4-under 68 and is alone in fifth place at 14-under-par 202.
Adam Blyth (70), Wen-Chong Liang (66), Oliver Fisher (67), Brad Kennedy (69) and James Heath (68) are tied for sixth place at 13-under-par 203.