big enchilada vs head honcho

big enchilada and head honcho both are nouns.

Word	Noun	Adjective	Verb	Adverb
big enchilada	Yes	No	No	No
head honcho	Yes	No	No	No

As nouns, big enchilada and head honcho are synonyms defined as:

Other synonyms of big enchilada include big cheese, big deal, big fish, big gun, big shot, big wheel.

big enchilada (noun)	head honcho (noun)
an important influential person	an important influential person