Solving the hydra-headed economic, technical and institutional electrification challenges in the Nigeria Power sector requires innovative insights that decentralized offgrid reverse auction with solar power plus storage offers. However, running a successful auction requires a meticulous design with in-depth understanding of the environment and data access to provide insight on what capacity to procure, locations, costs and regulatory governance. Combining GIS, energy system optimization and market/regulation design expertise, we contribute to bridging this knowledge gap for the Nigeria Power sector. We identified the most populated consumer clusters without electricity access, made load demand projections and determined the techno-economically optimized PV plus battery storage sizes to achieve high quality power supply with some demand side management. Furthermore, we analysed the land requirements/availability to achieve a shortlist of 233 clusters with 7.2 million people that require 3280 MW solar PV for the proposed auction. Finally, we discussed the pathway to adapt our design to the existing market/regulatory framework.