Edwards led a race-high 71 laps and held off Brian Vickers in the final laps before the race ended under a caution flag.
Edwards, who celebrated his 29th birthday Friday, earned his third Nationwide victory of the season and the 16th of his career.
He led the field to the green flag after winning the pole earlier in the day. But the first caution flag was quickly displayed when Mark Green and Steve Wallace spun on the first lap.
Brian Vickers finished second, Tony Stewart third, Mark Martin fourth and Greg Biffle fifth.
"If the caution would have come out about 300 yards sooner, we would have a chance," Vickers said. "We were running him down there at the end."