The 29-year-old Chastain from Alva, Florida, rallied from an early pit road speeding penalty to overtake Erik Jones on the final lap through the tri-oval to claim his second career win in NASCAR's premier series.
The NASCAR Cup Series and Xfinity Series travel to Talladega Superspeedway this weekend. The ARCA Menards Series will also complete Saturday afternoon in the General Tire 250.
The two-time Cup champion from Las Vegas, Nevada, benefitted from a final lap collision involving Tyler Reddick and Chase Briscoe to become the ninth different competitor to reach 60 victories in NASCAR's premier series.
The NASCAR Cup Series and Camping World Truck Series travel to Bristol Motor Speedway this week for some dirt track racing under the lights while the Xfinity Series is off.
The 24-year-old Byron from Charlotte, North Carolina, led a race-high 212 of 403 and fended off Joey Logano during an overtime shootout to repeat as a Cup winner at the Paperclip-shaped short track.
Denny Hamlin passed William Byron with five laps remaining and held off Kevin Harvick to win the Toyota Owners 400 Richmond. It was Hamlin's first win of the year as well as his first top 10 of the year.
