Green’s Dictionary of Slang

chub n.²

a Texan.

1869

‘South-Western Sl.’ in Overland Monthly (CA) Aug. 129: For the Texan soubriquet ‘Chub’ I know of no explanation, unless it be found in the size of the Eastern Texans. It is related of the Fifteenth Texas Infantry, for instance, that at the mustering-in no member was of a lighter weight than a hundred and eighty pounds, while a large number made the scale-beam kick at two hundred.