We report the fabrication of silicon nanopillar-based nanocapacitor arrays using metal-assisted etching in conjunction with electrodeposition. The high aspect ratio made possible by the catalyzed etching provides for an increased effective electrode area and hence a significant improvement in the capacitance density. Electroplated Ni electrode forms a conformal layer over the silicon nanopillars. Capacitance measurements show the expected trend as a function of pillar height and array period. The fabrication approach is simple, compatible with integration into standard silicon technology, and easily scalable.