Old Nick vs Satan

Old Nick and Satan both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old Nick	Yes	No	No	No
Satan	Yes	No	No	No

As nouns, Old Nick and Satan are synonyms defined as:

Old Nick and Satan: (Judeo-Christian and Islamic religions) chief spirit of evil and adversary of God; tempter of mankind; master of Hell

Other synonyms of Old Nick include Beelzebub, Devil, Lucifer, Prince of Darkness, the Tempter.

Old Nick (noun)	Satan (noun)
(Judeo-Christian and Islamic religions) chief spirit of evil and adversary of God; tempter of mankind; master of Hell	(Judeo-Christian and Islamic religions) chief spirit of evil and adversary of God; tempter of mankind; master of Hell