Old Nick vs Devil

Old Nick and Devil both are nouns.

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

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

Old Nick and Devil: (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, Lucifer, Prince of Darkness, Satan, the Tempter.

Old Nick (noun)	Devil (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