painting vs coating

painting and coating both are nouns.

Word	Noun	Adjective	Verb	Adverb
painting	Yes	No	No	No
coating	Yes	No	No	No

As nouns, coating is a hypernym of painting; that is, coating is a word with a broader meaning than painting:

Other hypernyms of painting include application, covering.

painting (noun)	coating (noun)
creating a picture with paints	the work of applying something
the occupation of a house painter	a thin layer covering something
the act of applying paint to a surface	a heavy fabric suitable for coats
graphic art consisting of an artistic composition made by applying paints to a surface	a decorative texture or appearance of a surface (or the substance that gives it that appearance)