  eHWC J2019+368 is one of the sources emitting $\gamma$-rays with energies
higher than 100 TeV based on the recent measurement with the High Altitude
Water Cherenkov Observatory (HAWC), and the origin is still in debate. The
pulsar PSR J2021$+$3651 is spatially coincident with the TeV source. We
investigate theoretically whether the multiband nonthermal emission of eHWC
J2019+368 can originate from the pulsar wind nebula (PWN) G75.2$+$0.1 powered
by PSR J2021$+$3651. In the model, the spin-down power of the pulsar is
transferred to high-energy particles and magnetic field in the nebula. As the
particles with an energy distribution of either a broken power-law or a
power-law continually injected into the nebula, the multiband nonthermal
emission is produced via synchrotron radiation and inverse Compton scattering.
The spectral energy distribution of the nebula from the model with the
reasonable parameters is generally consistent with the detected radio, X-ray
and TeV $\gamma$-ray fluxes. Our study supports that the PWN has the ability to
produce the TeV $\gamma$-rays of eHWC J2019+368, and the most energetic
particles in the nebula have energies up to about $0.4$ PeV.
