  Electroweak scale higgsinos with a nearly degenerate spectrum in
supersymmetric models are well-motivated, but generally less constrained at
collider experiments as the decay products are often too soft to detect.
Initial photon fusions alongside the collision of protons at the Large Hadron
Collider (LHC) have drawn attention recently as a way to search for new physics
with such kind of spectra. In this paper, we demonstrate a search strategy for
chargino pair production from photon fusion $pp\to
p(\gamma\gamma\to\tilde{\chi}^{+}_{1}\tilde{\chi}^{-}_{1})p$ at the 13 TeV LHC
via the semileptonic decay channel, as a probe for the compressed spectra of
higgsinos. Forward detectors make it possible to detect the outgoing protons
after emitting the initial photons in these processes. We here provide simple
event selections on missing energy and transverse momentum of leptons, which
are effective enough to reach significant sensitivity. The chargino mass can be
excluded at 95\% C.L. up to about 295 GeV with the mass difference $\Delta
m(\tilde{\chi}^{\pm}_{1},\tilde{\chi}^{0}_{1})$ being only a few GeV with the
integrated luminosity of 3 ab$^{-1}$. With a relatively small luminosity of 100
fb$^{-1}$, the $2\sigma$ exclusion bounds can as well exceed current
experimental limits in the range of $\Delta m=1\sim2$ GeV, reaching over 190
GeV for chargino mass.
