Chop is here used in the 16th-century sense meaning bandy words. This sense is now obsolete and the sense of chop used in this phrase was later wrongly understood as cut something into small pieces.
Related Idioms :
bust his chops
nag or criticize someone - North American informal
bust your chops
exert yourself - North American informal
chop and change
change your opinions or behaviour repeatedly and abruptly, often for no good reason - British informal
Both chop and change originally had the sense of barter, exchange or buy and sell…but as this sense of chop became dated the meaning of the whole expression shifted to its present one.
not much chop
not up to much - Australian & New Zealand informal
The sense of chop in this expression originated in the Hindi word châp meaning official stamp. Europeans in the Far East extended the use of the word to cover documents such as passports to which an official stamp or impression was attached and in China it came to mean branded goods. From this, in the late 19th century, chop was used to refer to something that had class or had been validated as genuine or good.
1947 - Dan Davin - The Gorse Blooms Pale - I know it's not been much chop so far but we're only getting started.