big shot vs big enchilada

big shot and big enchilada both are nouns.

Word	Noun	Adjective	Verb	Adverb
big shot	Yes	No	No	No
big enchilada	Yes	No	No	No

As nouns, big shot and big enchilada are synonyms defined as:

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

big shot (noun)	big enchilada (noun)
an important influential person	an important influential person