  The Galactic Center Excess (GCE) is explained in the framework of the
Next-to-Minimal Supersymmetric Standard Model (NMSSM) with a $Z_3$ discrete
symmetry. We show that a resonant CP-odd Higgs boson with mass twice that of
the Dark Matter (DM) candidate is favoured. Meanwhile, the DM candidate is
required to have relatively large coupling with the $Z$ boson through its
Higgsino component in order to obtain correct DM relic density. Its LHC
discovery potential via four signatures is discussed in detail. We find that
the most sensitive signals are provided by the Higgsino-like chargino and
neutralino pair production with their subsequent decays into $W$ bosons, $Z$
bosons, and DM. The majority of the relevant parameter space can be probed at
the Large Hadron Collider with a centre-of-mass energy of 14 TeV and an
integrated luminosity 1000 fb$^{-1}$.
