  Manipulating oxygen vacancies in strongly correlated rare-earth nickelate
perovskites (RNiO$_3$) enables the tuning of their elusive metal-insulator
transition (MIT), providing a better handle for control over their electronic
properties. In this paper, we investigate the effect of various oxygen vacancy
configurations on the MIT of LaNiO$_3$ by studying their spectral functions and
the corresponding diffusion energy path using dynamical mean field theory
(DMFT) and density functional theory plus U (DFT+U). To consider all possible
configurations for a fixed vacancy concentration, we use a symmetry-adapted
configurational ensemble method. Within this method, we can reduce the
configurational space which needs to be considered, thus lowering the
computational cost. We demonstrate that controlling the oxygen vacancy position
can tune the occurrence of MIT. We also show that the nudged elastic band (NEB)
energy barrier heights and energy profile obtained using DMFT are lower and
different than those obtained using DFT+U due to dynamical quantum fluctuations
among non-degenerate correlated orbitals not properly treated in DFT+U.
