  In the present work, we investigated the electronic and elastic properties in
equilibrium and under strain of the type-II Dirac semimetal NiTe$_2$ using
density functional theory (DFT). Our results demonstrate the tunability of
Dirac nodes' energy and momentum with strain and that it is possible to bring
them closer to the Fermi level, while other metallic bands are supressed. We
also derive a minimal 4-band effective model for the Dirac cones which accounts
for the aforementioned strain effects by means of lattice regularization,
providing an inexpensive way for further theoretical investigations and easy
comparison with experiments. On an equal footing, we propose the static control
of the electronic structure by intercalating alkali species into the van der
Waals gap, resulting in the same effects obtained by strain-engineering and
removing the requirement of in situ strain. Finally, evaluating the
wavefunction's symmetry evolution as the lattice is deformed, we discuss
possible consequences, such as Liftshitz transitions and the coexistence of
type-I and type-II Dirac cones, thus motivating future investigations.
