head honcho vs big wheel

head honcho and big wheel both are nouns.

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

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

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

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