This article investigate the impact of thermal instability on heat transfer of micropolar nanofluid saturated in porous medium with rotation in linear and nonlinear ways. The truncated Fourier series approach is used to analyze nonlinear stability, while analytical evaluation of linear stability is performed with normal mode methodology. Based on outcomes, the micropolar and rotation parameter has stabilizing effect in the system. As opposed to that, nanoparticle Rayleigh number, porosity parameter and Lewis number accelerate the start of convective motion inside the system. Some parameters play a significant influence in transport of heat and mass in non-linear analysis. The rotation parameter, micropolar parameter, perform a major contribution in heat/mass transfer in the system. Mass/heat transfer in the system is analyzed by two different approaches, Mathematica NDSolve and Runge-Kutta-Fehlberg method(RKF-45), and it is found that the rate of mass/heat transfer is exactly the same in both cases.