Busch, a Sprint Cup Series regular, led the most laps with 156 but had to fend off a hard-charging Larson in the closing laps. He beat Larson by 0.023 seconds, making it the second closest finish in a Nationwide race at this 0.533-mile, high-banked oval.
In the August 2011 Nationwide event at Bristol, Busch beat his then Joe Gibbs Racing teammate Joey Logano to the finish line by only 0.019 seconds.
Brian Vickers, who is Busch's teammate at Joe Gibbs Racing, finished third. Sam Hornish Jr., the current points leader and last weekend's race winner at Las Vegas, placed fourth. Kevin Harvick completed the top-five.
Busch has now extended his Nationwide record of career victories to 53. He won two weeks ago at Phoenix.
On Friday, Busch set a new track qualifying record at Bristol to win the pole for Sunday's scheduled 500-lap race here.