A boundary layer analysis is laid out for the steady, laminar, mixed convection flow past an isothermal vertical cone embedded in a porous medium filled with a nanofluid. The model used for the nanofluid is one which includes the effects of Brownian motion and thermophoresis. A parametric study is performed for different physical parameters, such as magnetic (M), cone angle (m), mixed convection (χ), Brownian motion (Nt), and thermophoresis (Nb), on the velocity, temperature, and nanoparticle concentration profiles. The local Nusselt, Sherwood, and nanoparticle Sherwood number have been laid out in a graphical way. The dependency of the rate of heat and mass transfer on the governing parameters has been discussed.