The enhanced performance and reduced scale that nanoparticles can bring to a device are frequently compromised by the poor electrical conductivity of nanoparticle structures or assemblies. Here, we demonstrate a unique nanoscale electrode assembly in which conduction is carried out by one set of nanoparticles, and other device functions by another set. Using a scalable process, nanoparticles with tailored conductivity are stochastically deposited above or below a functional nanoparticle film, and serve as extensions of the bulk electrodes, greatly reducing the total film resistance. We apply this approach to solid-state gas sensors and achieve controlled device resistance with an exceptionally high sensitivity to ethanol of 20 ppb. This approach can be extended to other classes of devices such as actuators, batteries, and fuel and solar cells.