He isn't lying, he is just ignorant. Like most "students" of the Bible and its associated texts which hold no historic value as the dates of the individuals lives are almost always wrong or contested.

Niniveh is a very well established and incredible archeological site that has given us a wealth of knowledge of pre-dynastic as well as dynastic Mesopotamia.

It is a very real place and we already know exactly where it is because they have been excavating it since the 1930's.

Again, OP is just ignorant, and hasn't heard of the Library of Ashurbinapal, possibly one of the most important finds in archeology.