  We construct multibump nodal solutions of the elliptic equation $$ -\Delta
u=a^+[\lambda u+ f(\, \cdot\,, u)]-\mu a^- g(\, \cdot\,, u) $$ in
$H^1_0(\Omega)$, when $\mu$ is large, under appropriate assumptions, for $f$
superlinear and subcritical and such that the eigenvalues of the associated
linearized operator on $H^1_0(\{x\in\Omega:\: a(x)>0\})$ at zero, $u\longmapsto
u-\lambda(-\Delta)^{-1}(a^+ u)$, are positive. The solutions are of least
energy in some Nehari-type set defined by imposing suitable conditions on
orthogonal components of functions in $H^1_0(\Omega)$.
