1970s; earliest use found in American Behavioral Scientist. Shortened from nunchaku (with loss of final vowel probably reflecting partial devoicing of -u in spoken Japanese). Forms with -chuck show alteration after chuck.
nunchuck2
/ˈnʌntʃʌk/
(also numchuck, nunchuk)
verb
[with object]To hit (a person or thing) with a nunchuck. Also (in extended use): to fell, defeat, browbeat.
Origin
1990s; earliest use found in InfoWorld. From nunchuck.