This paper is a conceptual proposal for conducting a mixed-method multiple case study on a consumer behaviour topic in an emerging nation. Government administrators and marketing managers need current, reliable consumer behaviour models to serve the public and to achieve a profitable return on investment in Nigeria. There is a shortage of online consumer behaviour research in some highly populated emerging economies in Africa, such as in Nigeria, especially concerning the influence of demographic and socio-cultural factors. The purpose of this study will be to produce a visual, conceptual model of consumer decision making factors for the unique socio-cultural population. The purpose of this study is to scientifically explore the ground truth of Nigerian consumer online purchasing decisions to build a practical model for e-commerce stakeholders. The results of this study should be interesting for other researchers due to the novel sequential mixed-method grounded theory and multiple case study literal replication design. Nigerian e-commerce marketing managers and policymakers in the population could benefit financially from this extension to the body of knowledge.