viewing vs showing

viewing and showing both are nouns.

Word	Noun	Adjective	Verb	Adverb
viewing	Yes	No	No	No
showing	Yes	No	No	No

As nouns, viewing and showing are synonyms defined as:

Other synonyms of viewing include screening.

viewing (noun)	showing (noun)
a vigil held over a corpse the night before burial	something shown to the public
the display of a motion picture	the display of a motion picture