  We show that the nonlinear chiral supermultiplet allows one to construct,
over given two-dimensional bosonic mechanics, the family of two-dimensional
${\cal N}=4$ supersymmetric mechanics parameterized with the holomorphic
function $\lambda (z)$. We show, that this family includes, as a particular
case, the ${\cal N}=4$ superextensions of two-dimensional mechanics with
magnetic fields, which have factorizable Schroedinger equations.
