The question uses the wrong words when it pertains to causes of disordered behavior. The word "nurture" gives the connotation of mother love, bonding, family life, and that's what most of us think of when arguing the question. But if the definition of nature involves only genetics, as is generally assumed, then whatever else affects behavior must be nurture, in addition to the psychological environment. Thus, nurture causes must include a blow to the head, improper nutrition (prenatal or post-natal), birth trauma such as oxygen deprivation, chemical toxicity, or allergic-like reactions to certain foods or chemicals.
The problem becomes further blurred. For example, research reports on the importance of bonding between infants and parents seldom take into consideration the fact that some children are born far more easy to bond with than others. And individuals with allergic-like reactions—an environmental influence— may be genetically predisposed to these reactions.
Nevertheless, the question would be better understood if it read, "Genetics vs. Environment." Or perhaps it shouldn't even be asked; researchers such as Clark and Grunstein (see related article, Crime Times, 2001, Vol. 7, No. 4, Page 6) report that the two influences interact and do not oppose each other.