The objective of this work is to scrutinize the entropy production and its effects on Carreau nanofluid flow over a horizontally stretching cylinder. The significant influence of magnetic field, non-linear thermal radiation and Joule heating have been studied to control the heat transfer rate. The importance of nanofluid parameters, Brownian and thermophoresis diffusion, is argued on Carreau nanofluid motion for shear-thinning and thickening behavior. Utilizing convenient transformations, the fundamental equations, devised to a nonlinear system of ordinary differential equations (ODEs), are resolved numerically by Matlab technique bvp4c. The influence of relevant parameters on velocity, Bejan number, temperature, entropy and concentration profiles are examined by virtue of graphs. Furthermore, we determine the repercussion of indistinguishable parameters over skin friction and Sherwood number via tables. From the acquired results, we perceive that entropy generation augments with enhancing magnetic field parameter, Brinkman number, curvature parameter, Eckert number, and power law index while it declines for the Brownian diffusion parameter. Also, skin friction reduces for the magnetic field and curvature parameter whereas it rises for Weissenberg number. Moreover, Sherwood number escalates for the Schmidt number and curvature parameter.