This study investigates lean principles among Nigerian entrepreneurs and SME managers in the operational process in the aftermath of COVID-19 pandemic in Nigeria. It offers the panacea to the challenge of social-economic shocks and their adverse effects on SMEs' business activities in Nigeria. The study adopts a conceptual approach to investigate lean entrepreneurship practice by SMEs in Nigeria. It relies on data from extant literature, using a conceptual approach to examine the social-economic effects of COVID-19 pandemic and critical environmental factors on the lean entrepreneurship practice in Nigeria. Furthermore, the study explores the influence of lean practice among SMEs and entrepreneurs in Nigeria and suggests a broad model for lean entrepreneurial practice in post-COVID-19 pandemic Nigeria. Findings highlight the broad social-economic effects of COVID-19 pandemic and other challenges such as theft, host community pressure, weak legal system, and inadequate government policy support affect lean entrepreneurship practice. These factors constitute complex operational issues that would require the adoption of a more comprehensive approach to address. It also highlights crucial factors for post-COVID-19 pandemic SMEs' operational success in Nigeria due to deficits in infrastructure and regulatory efficiency for SMEs' operations to address the various challenges of business failures in Nigeria. The study suggests a lean SME and Entrepreneurial Practice model in the post-COVID-19 pandemic era. It emphasises the need to refocus the active interest of the lean entrepreneur on critical business sustainability. The study recommends a critical review of the internal operational process among practicing entrepreneurial businesses and a re-modification of public policies system that governs the operational functions of entrepreneurial practices for reasonable and resilient post-COVID-19 pandemic entrepreneurship practices that can support the SMEs and economic growth in Nigeria.