big enchilada vs big wheel

big enchilada and big wheel both are nouns.

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

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

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

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