In this work steady natural convection flow energized by an exothermic chemical reaction administered by Arrhenius kinetics inside a tilted nanofluid saturated porous square cavity under the action of a sloping magnetic field has been deliberated numerically following Buongiorno nanofluid model. It is assumed that there is a local thermal equilibrium state between the considered nanofluid and homogeneous porous medium. The mathematical model governing the dimensionless stream function for flow, temperature for heat, and nanoparticles volume fraction for concentration are simulated numerically by means of Galerkin weighted residual type of finite element method. The numerical code has been corroborated compared with the formerly available works, and very good agreement is noticed among the outcomes. Disseminations of streamlines, isotherms, isoconcentrations, and average Nusselt number at wide-ranging key parameters are acquired and discussed in details. The results show that Rayleigh and Frank-Kamenetskii numbers strongly control the convective flows. The average Nusselt number increases with the Frank-Kamenetskii number while it decreases with the Rayleigh number. Heat generation due to a strong exothermic reaction (higher Frank-Kamenetskii number) can blow up the bounded solution. For higher Frank-Kamenetskii number, the rate of heat transfer can be controlled tilting the cavity anticlockwise. Magnetic field slope overwhelms the heat transfer rate when the Frank-Kamenetskii number is high. A strong magnetic field caused the nanoparticles separation for the slow flow. Effects of Brownian diffusion and thermophoresis on average Nusselt number are minimal while their effects on average Sherwood number are quite accountable. Crown Copyright (C) 2018 Published by Elsevier Ltd. All rights reserved.