nag vs quetch

nag is a noun but quetch is not a noun.

Word	Noun	Adjective	Verb	Adverb
nag	Yes	No	Yes	No
quetch	No	No	Yes	No

As verbs, quetch is a hypernym of nag; that is, quetch is a word with a broader meaning than nag:

Other hypernyms of nag include complain, kick, kvetch, plain, sound off.

nag (noun)	quetch (noun)
an old or over-worked horse
someone (especially a woman) who annoys people by constantly finding fault

nag (verb)	quetch (verb)
remind or urge constantly	express complaints, discontent, displeasure, or unhappiness
bother persistently with trivial complaints
worry persistently