ordqvist shot a 5-under-par 67 to bring her three-round total to 11 under on Saturday, four ahead of her nearest rivals.
Chasing the Swede are Inbee Park of South Korea, who won the tournament last year and is ranked No. 1 in the world, and Michele Wie of the United States, both at 7 under. Julieta Granada of Paraguay is one shot further back.
Another shot behind were Americans Lexi Thompson and Kristie Kerr, along with New Zealand teenager Lydia Ko and Yani Tseng of Taiwan, who has won the Thailand event twioce before.
Thailand's Thidapa Suwannapura completed her round in 3 under par and remained the top local contender at one under.
Pornanong Phatlum, who won $600,000 as the top Thai player on the LPGA Tour last year, was at one over after a second consecutive round of one over par.
Ariya Jutanugarn, who led last year's Open before losing to Park on the 72nd hole, fell back to 7 over, while sister Moriya was at 3 over par.
Nordqvist said she was delighted to be leading the tournament for the third straight day.
"To be in contention on the final day is all you can ask for," she said, though she admitted her third round took a while to spark.
"I played solid but was on even-par at the turn and knew I had to remain patient."
The Swede's patience was rewarded with a magnificent second shot on the 10th which left her little more than a tap-in for a stunning eagle.
"I hit a perfect fade," she said. "The 10th gave me the momentum I needed."
She went on to sink three more birdies on the back nine including the difficult 18th.
World number one Park admitted she had been nervous in her first tournament of the year, but felt a lot more comfortable after shooting 67 which featured six birdies and one bogey.
"I hit a lot of great shots today, but I left four or five birdies out there," she said. "My putter wasn't as hot as my ball-striking."
Park said that winning the event last year set her up for a great season.
"If I can win this week, it would be a good lucky charm," she added.
Wie, a former teenage phenomenon who has never realised her full potential on the Tour, was happy to be in the mix for the final day.
"I had a really fun day," she said. "I didn't really take advantage of the par-fives, but I hope to do that tomorrow. There are birdies out there."
Concerning her improved form, Wie said she believed it was partly due to a good off-season break.
"I took a very nice mental vacation. I went home for five weeks and didn't take my clubs."