The 2015 Paris Agreement (COP21) mandated countries to submit their Intended Nationally Determined Contributions (INDC). In this paper, we develop the TIMES-Nigeria model and applied it to assess the impacts of Nigeria's NDC mitigation strategies and the ripple effects on the energy system. To this end, we modelled four mitigation scenarios in addition to the reference scenario. Increased renewables penetration, energy efficiency improvements, and fuel switching are identified as key mitigation strategies in the Nigerian NDC. Our results reveal profound restructuring of the Nigerian energy system with changes in the supply mix which mainly favour the deployment of solar PV. Our analysis shows that the residential sector has the largest potential for reducing energy demand while the power sector should be the focus for CO2 emissions mitigation. Furthermore, we explore the impacts of carbon tax on the energy system. Our analysis discloses a significant improvement in energy security due to mitigation actions. We also shed lights on the local and international implications of the results. While our analysis should be counted as a preliminary study because of limited available country data, the outcomes are expected to provide useful insights with respect to low-carbon transition in the country. Display omitted •We introduce a new bottom-up technology-rich energy system model: TIMES-Nigeria.•We examine possible scenarios for low-carbon transitions in Nigeria up to 2050.•Profound structural effects induced in the energy system.•Carbon tax can potentially reduce energy-related emissions by around 77%.•Mitigation actions will boost energy security.