Starting on the back nine, the 26-year-old American birdied the 11th and then caught fire from the par-three 13th when his tee shot nearly found the cup. He went on to make the birdie putt and card more birdies on his next five holes.
Trailing Schauffele were overnight leader Tyrrell Hatton and Matthew Fitzpatrick from England and his compatriot Russell Henley, who were all eight-under par for the tournament.
The CJ Cup was switched to Shadow Creek in Las Vegas from South Korea this year because of travel restrictions imposed due to the COVID-19 pandemic.
There is no cut at the 78-player event, which includes many of the world's top golfers. (Reporting by Rory Carroll in Los Angeles; Editing by Ken Ferris)