Just a though, in general giving animals as gifts its a very bad idea specialy for a child, insted I highly recomend that you offer a good care giving book about one of thouse species or another reptile related theme for your nephew to read and learn all about them before making a responsable purchase. A very good book would be one of the reptilia edicions or the begginer vivarium series. At the very least make shure he knows thouse species including all the logistics of keeping life food around, heating ,etc