  In this Letter, we study the spin Nernst effect (SNE) of magnons in the
nonlinear response regime. We derive the formula for the nonlinear magnon spin
Nernst current by solving the Boltzmann equation and find out that it is
described by an extended Berry curvature dipole of magnons. The nonlinear
magnon SNE is expected to occur in various N\'eel antiferromagnets without
Dzyaloshinskii-Moriya interaction. In particular, the nonlinear spin Nernst
current in the honeycomb and diamond lattice antiferromagnets can be controlled
by strain/pressure.
