nonexistent vs being

nonexistent is not a noun while being is a noun.

Word	Noun	Adjective	Verb	Adverb
nonexistent	No	Yes	No	No
being	Yes	No	No	No

nonexistent (noun)	being (noun)
	a living thing that has (or can develop) the ability to act or function independently
	the state or fact of existing

nonexistent (adjective)	being (adjective)
not having existence or being or actuality