The fact of the matter is that most people who buy hatchling nile monitors at shows don't know what they're doing, don't take care of it properly, and it usually dies withing a few months.
Its sad, but it happens to thousands of imported monitor lizards year after year.
I was sitting behind some tables at a show recently and watched one vendor sell out of 100 baby savannah monitors in 3 hours, $15 a piece. All went to little kids, teenage girls, etc, who will probably stick them in a 10 gal tank with a light bulb, where they might survive for 3 months, if that. They are almost like disposable pet. Its sickening.