The present article enlightens us on the hydrothermal pattern of a steady incompressible laminar natural convective nanofluid flow inside a heated square chamber.The square enclosure is filled with water-based sphericalshaped ferrous (Fe 3 O 4 ) nanoparticles. Magnetic effect and thermal radiation are presumed within the flow. The leftsided vertical wall and one bottom wall of the chamber are nonuniformly and uniformly heated, while the remaining right-sided vertical wall is isothermally cooled at a constant temperature and the upper wall is insulated. A detailed analysis is conducted to exhibit that how nonuniform and uniform heated walls influence flow within the square chamber. The leading dimensional equations are made into a dimensionless form using apposite similarity variables and the Galerkin finite element technique is executed to solve those equations. The grid independence test and a parallel comparison with existing literature are presented to verify the validity of the outcomes. The streamlines, isotherms, temperature, velocities, and average Nusselt number are depicted through several graphs for several parametric values of Rayleigh number, Hartmann number, thermal radiation, and nanoparticle volume fraction. The outcomes showed that increasing nanoparticle concentration and Rayleigh number lead to