Bryant MacKellar, a Monday qualifier, fired an 8-under 64 in the third round and is alone in third place at 19-under-par 197.
Chopra and Langham, both of whom shared the 36-hole lead with Scott Sterling, played in Saturday's final group and were tied for first after each went 2 under on their front nine.
Chopra made the first move to the top spot at the 12th. He reached the green in two from 280 yards out and two-putted from 60 feet for birdie and sole possession of the lead.
Langham answered at 14 with a 12-foot birdie putt but the tie was short-lived as Chopra ran home a 10-footer of his own to reclaim a one-shot lead. Both players went for the short par-4 15th off the tee and both landed left of the green. Langham pitched 15 feet short of the hole while Chopra chipped 8 feet right of the flag. Langham missed his birdie putt but Chopra converted his to go up by two.
The duo tallied matching birdies at No. 16, both from inside 10 feet, and each had a reasonable look at birdie at the par-3, 243-yard 17th. Neither made their 25-foot chance but both looked to take advantage of the par-5 closing hole.
Chopra missed the fairway left and Langham landed in the first cut on the same side. Langham elected to lay up short of the green while Chopra played a difficult iron shot through trees into the right, greenside bunker. Langham pitched to 5 feet and Chopra blasted to nearly the exact same spot.
Both players sank their birdie putts to keep Chopra's two-shot lead.
'I feel like if the shot is there to be hit, I go for it,' said Chopra, referring to his tough shot at 18. 'The riskier shot I was thinking about was a 6-iron and hook it over the water. Something in my head told me to play a little safer than that.'
Chopra is a member of the PGA Tour but since this week's event, the Colonial, is an invitational, he decided to tee it up for only the second time this season on the Nationwide Tour.
His other start was at the First Tee Arkansas Classic and he won the event. Now, instead of coming in the top-125 on the PGA Tour money list to keep his PGA Tour card next year, he has options.
If Chopra makes it to the winner's circle on Sunday, he will be one victory away from an automatic 'battlefield exemption' to the PGA Tour, which takes care of the rest of 2004 and 2005. If he doesn't win this week and continues to play well in limited starts on the Nationwide Tour, a top-20 on that money list will get him to the PGA Tour next year.
'I have thought about it but nothing you really consider seriously,' Chopra admitted. 'It's something I have an opportunity to do. I'm in position to get the second win. That's what you play for, to win tournaments.'
Langham will start the final round two back despite a 5-under 67 on Saturday.
'I blew up today,' kidded Langham. 'I'm never going to shoot 67 and say I'm unhappy. I feel good about my round. I played real solid. I didn't quite make the putts I've been making the first few days, but I made enough.'
Johnson Wagner held a piece of the lead on Saturday but back-to-back bogeys on the second nine cost him. He still shot a 7-under 65 and is tied for fourth place with Nathan Green and Ryuji Imada. That duo carded rounds of 67 and the trio is knotted at 18-under-par 198.
Sterling managed a 1-under 71 and shares seventh place with Jimmy Walker (66) at minus-17. If Walker can hoist the trophy on Sunday, he will earn the automatic pass to the PGA Tour thanks to a pair of wins earlier this season.