Van Pelt, the winner of the PGA Tour's 2009 U.S. Bank Championship in Milwaukee, had a 16-under 197 total at The Mines in the second-year event sanctioned by the PGA Tour and Asian Tour.
"I just love to play to compete," Van Pelt said. "It's not about the money. That's what gets my juices flowing. Like my grandpa always told me, 'You can't take it with you.'
"Obviously, any time you're near the lead with 18 to go, you're excited. That's why we practice and why we enter tournaments. That's all you can ask for, to have a chance to win on Sunday. It's exciting, and I'm looking forward to it. It's been a while since I won a golf tournament, so it would be great."
Overton, tied for second-round lead with Sweden's Fredrik Jacobson after a course-record 62, had a 69.
"It wasn't my day on the greens," Overton said "Didn't make anything."
Overton noted the Hoosier connection at the top of the leaderboard.
"It's crazy," Overton said. "We're from the same state, Indiana, and probably the only two players in the field or on tour from Indiana. To actually come all the way here, a 12-hour time change, halfway around the world to play golf with each other, it'll be fun."
Jacobson (71) and Mark Wilson (67) were 13 under.
Van Pelt bogeyed the opening two holes, but countered with birdies on Nos. 3 and 5. He also birdied the 12th and made three more on Nos. 15-17.
"I didn't make a big deal after bogeying the opening two holes," the former Oklahoma State star said. "I told myself it wasn't the end of the world and just concentrated on playing my shots.
"I think that's the biggest thing I've learned, experience-wise. As much as golf as I've played, in the times I've let a bad start lead to a bad round, it was probably when I made too big a deal out of it, got upset or got quicker (with my swing). I think today was just a good example of not making a big deal out of it and trying to hit good golf shots."
"I guess the expectation is building up now," Chia said. "Every day when I begin my round, I don't really think about the result. I just want to play my golf. I only started looking at the leaderboard on the second-to-last hole and told myself, 'Hey, I still got an outside chance.' "
Defending champion Ben Crane was 8 under after a 68.
The winner will receive $1.3 million from the $6.1 million purse.