Bioconvection in magneto-nanoliquid embedded with gyrotactic microorganisms across an elongated sheet with velocity slip of second order is addressed. Nonlinear thermal radiation and chemical reaction aspects are retained in energy and concentration equations. Numerical simulations for the modeled problem are proposed via Runge–Kutta–Fehlberg-based shooting technique. Special attention is given to the impact of involved parameters on the profiles of motile microorganisms, nanoparticle volume fraction, temperature and velocity. Our simulations figured out that assisting flow generates more heat transfer than the opposing flow situation. The motile microorganism’s boundary layer decayed for higher bioconvection Peclet and bioconvection Lewis numbers.