  We obtain novel nonlinear Schr\"{o}dinger-Pauli equations through a formal
non-relativistic limit of appropriately constructed nonlinear Dirac equations.
This procedure automatically provides a physical regularisation of potential
singularities brought forward by the nonlinear terms and suggests how to
regularise previous equations studied in the literature. The enhancement of
contributions coming from the regularised singularities suggests that the
obtained equations might be useful for future precision tests of quantum
nonlinearity.
