Michelle Wie limped around the back nine of the Emirates Golf Club because of a bad back and finished with a 72, six shots behind the leader.
Hall had a 31 on the front nine, including five birdies, to move to the top at the season-ending tournament.
England’s Laura Davies all but conceded the Order of Merit for the top golfer in Europe to South Africa’s Lee-Anne Pace. Davies shot a 73 and is 11 strokes behind the leader. She needs to finish in the top two to overtake Pace, who had a 72.
Wie withdrew from last month’s Lorena Ochoa Invitational because of the injury, but said she expects to be healthy by the start of the season after some rest and rehabilitation.
Wie winced several times after drives off the tee and dipped her knees on the follow through. She said it wouldn’t have “long-lasting effects” and she expects to play a full schedule next season.
“I’m in survival mode right now. Hopefully I’ll go out there and grind it out in the next few days,” she said. “I’ve just got to get my irons closer. I’m not leaving myself a lot of birdies putts, makable ones.”
Hall, whose father played for the Wales rugby team, was in eighth place after the first round and wasn’t expected to make a run at the leaderboard.
“I just played really solid, approaches within 15 feet on the front nine,” said the 23-year-old Hall, who is ranked 396th. “I was really pleased. I made a couple of mistakes on 9 and 10, and three-putted on 10. I kind of refocused and moved onto 11 and made a good putt and kept doing it.”
She went into the water on the ninth hole and three-putted the 10th for another bogey before making birdies on her final two holes to regain the lead at 7-under 137.
Nordqvist made four birdies in a bogey-free round of 68, one shot ahead of Danish veteran Iben Tinning, who will retire after the tournament.
Tinning bogeyed the last two holes to lose a share of the lead, but remains in the hunt for a sixth career tour victory and first since 2005. Struggling with a long-standing hip injury, the 36-year-old Tinning said it would be “indescribable” to win in her final tournament.
“I’m not saying I don’t feel anything out there and definitely going for more pins,” Tinning said. “Why be a chicken at your last event?”
Three players were another shot back at 4 under, including Russia’s Maria Verchenova who needs a top-20 finish to retain her European Tour card. She is tied with England’s Melissa Reid (70) and Norway’s Marianne Skarpnord (71).
Davies was bothered by a lack of sleep before the first round, when she shot a 75.
“I didn’t play well again today. The timing is all out,” Davies said. “The tournament is over for me as far as I’m concerned. As for winning it or getting second place which we were trying to do, it’s not going to happen, so obviously I am disappointed.”
Pace said the pressure is off heading into the weekend.
“Now, I can sit back, relax and play the golf course and be at the top,” she said.