  Using quasiparticle self-consistent $GW$ calculations we examined the
electronic structure of LaNiO$_3$ and the LaNiO$_3$/LaAlO$_3$ superlattice. The
effects of electron correlation in Ni-$d$ bands were reasonably well described
without any {\it ad hoc} parameter and without the ambiguity related to the
double-counting and downfolding issues. The effective mass is about $30\%$
enhanced compared to the GGA result. One band feature, which is believed to be
essential for the cuprate-like superconductivity, is not realized and the
central Fermi surface pocket does not disappear. Our result is consistent with
a recent dynamical mean field calculation based on the $d$--$p$ model and in
contrast to the result from a $d$-band only model.
