Temperature-dependent DC transport measurements on self-assembled Ag nanoparticle monolayers have been obtained as a function of particle size distribution induced disorder. A transition temperature between the transport regimes of simple, activated transport to variable range hopping is observed to be in tune with increasing disorder of the monolayer. The overall transport behavior is described in terms of a mobility gap in the Anderson localized regime and an Efros-Shklovskii variable range hopping between localized states in the gap below some temperature characterized by the degree of disorder. From these results, we predict a true insulator-metal transition at narrow but still finite (<3%) size distributions.