This paper describes a pragmatic Model-Based Systems Engineering (MBSE) approach to reduce dependence on traditional documents and manage complexity of the electrified powertrain system. The approach enables requirements flow-down from an upper abstraction layer to the lower one(s) with stepwise analysis and design for a holistic system architecture of the system of interest. This approach is employed in the Nissan Powertrain development, which aims to solve challenges due to the traditional documents systems engineering (SE) approach to complex systems. This paper describes an MBSE approach developed for Nissan-7 methodology that focuses on knowledge cap-ture, fast feedback on requirements and design, and early verification and validation. The significant benefits of using an MBSE approach over a traditional documents SE approach are: a holistic view of system architecture, knowledge reusability, communicability, and adaptability to new technolo-gies. This paper presents proof of concept example projects that have demonstrated that it is viable to use this approach and apply it to an actual development for future work.