Driscoll shot a 6-under-par 66, while Snedeker posted a 5-under 67. They are knotted at 11-under-par 205, one shot ahead of Tom Scherrer, who fashioned a round of 3-under 69.
Thompson did not get off to an ideal start with one birdie and one bogey over his first four holes. He birdied two in a row from the seventh, but fell two off the lead of Driscoll and Snedeker, who were in the clubhouse, when Thompson three-putted for bogey at 13.
Things picked up quickly for Thompson with a birdie at 14. He birdied the 16th hole, then things really picked up for the 25-year-old from the University of South Carolina.
He missed the green with a 9-iron at the par-3 17th. Thompson's ball could have kicked into the hazard, but instead, Thompson chipped in for birdie.
'Every other time I've been in this position I've had some breaks that have gone against me,' said Thompson. 'I hit that one right of the green and it could have easily kicked into the hazard,' he said. 'Instead it stays up. I have a perfect lie from about 15 feet and I chip in.'
Thompson had one more magical shot up his sleeve. His 4-iron approach from 224 yards out at the par-4 18th skimmed the edge of the cup before stopping 3 feet from the hole. Thompson tapped in for the two-stroke lead.
'Not a bad finish, huh?' asked Thompson, who lost in a playoff to Kevin Stadler at the Scholarship America Showdown. 'I hit some good shots there. It could be my week, I don't know. I don't want to get ahead of myself, but anytime somebody wins, they always have stuff going on where they chip in. I witnessed it in Wisconsin with Kevin getting up-and-down from everywhere.'
Dave Cunningham (65), Richie Coughlan (68), Jake Reeves (69), Hunter Haas (70), Brian McCann (71) and Johnson Wagner (71) are knotted in fifth place at 8-under-par 208.
Michael Long's chance at Nationwide Tour history took a hit on Saturday. Long, who is trying to become the first player ever to successfully defend his title on this tour, was in the final group, but only managed an even-par 72 and is tied for 11th place at 7-under-par 209.