AbstractThis study discusses the impact of the nonlinear relationship between nonlinear density‐temperature and density‐concentration on a nanofluid flow with Arrhenius activation energy and sinusoidal wall temperature variations. The highly nonlinear partial differential equations that model the nanofluid flow are solved using the bivariate spectral local linearization method. In literature, it is known that certain thermal systems perform better at high temperatures. This performance may be influenced by the nonlinear temperature‐concentration‐dependent density relation, which accounts for optimal thermal and solutal transport in such systems. This study explores the impact of some physical parameters on the fluid transport properties, and the results show, among other findings, that the nonlinear density‐temperature leads to increased fluid velocity. In contrast, the nonlinear density‐concentration reduces the fluid speed. This study provides new insights into the impact of nonlinear density‐temperature and density‐concentration on fluid properties. Additionally, there is a development of destructive chemical reactions in the nanoparticle volume fraction profiles due to the Arrhenius activation energy.