head honcho vs big enchilada

head honcho and big enchilada both are nouns.

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

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

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

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