Transient electromagnetic (EM) scattering by conducting objects is formulated by time-domain magnetic field integral equation (TDMFIE). Traditionally, the TDMFIE is solved by combining the method of moments (MoM) in spatial domain and a march-on in time (MOT) scheme in temporal domain. We propose a different scheme in which the Nyström method is used in spatial domain while the MoM with Laguerre function as basis and testing functions is employed in temporal domain. The Nyström method is simple in implementation and does not require a basis or testing function and conforming meshes. The time-domain MoM can naturally enforce the causality and fully eliminate the numerical instability. A numerical example for EM scattering by a conducting cylinder is presented to demonstrate the approach and its merits can be observed.