viscera vs insides

viscera and insides both are nouns.

Word	Noun	Adjective	Verb	Adverb
viscera	Yes	No	No	No
insides	Yes	No	No	No

As nouns, viscera and insides are synonyms defined as:

viscera and insides: internal organs collectively (especially those in the abdominal cavity)

Other synonyms of viscera include entrails, innards.

viscera (noun)	insides (noun)
internal organs collectively (especially those in the abdominal cavity)	internal organs collectively (especially those in the abdominal cavity)