instigator vs troublemaker

instigator and troublemaker both are nouns.

Word	Noun	Adjective	Verb	Adverb
instigator	Yes	No	No	No
troublemaker	Yes	No	No	No

As nouns, troublemaker is a hypernym of instigator; that is, troublemaker is a word with a broader meaning than instigator:

Other hypernyms of instigator include bad hat, mischief-maker, trouble maker, troubler.

instigator (noun)	troublemaker (noun)
a person who initiates a course of action	someone who deliberately stirs up trouble
someone who deliberately foments trouble