What is the iguanodons common nick name?

There is no "nickname" for Iguanodon. Iguanodon is the scientific name for the genus, and the full Latin name for the only species in this genus is Iguanodon bernissartensis. Iguanodon means "iguana tooth" in while bernissartensis refers to Bernissart, Belgium, where the first nearly complete skeletons of Iguanodon were discovered.