Where did the term “chuckwagon” come from?

Where did the term "chuckwagon" come from? Michael Knapp Somers, Montana   Some say the term came from Charles (“Chuck”) Goodnight, who supposedly built the first meal on wheels—but that’s doubtful. The term dates from the late 19th century and is simply a compound word formed from chuck and wagon. “Chuck” had meant a piece of wood or meat since the 1670s, and it derives from “chock.” Chock referred to a lumpy piece of wood, which is pretty close to how chuckwagon food tast