  The recently discovered TeV emission from Gamma-Ray Bursts (GRBs) hints
towards a possible hadronic origin of this radiation component. We developed a
Monte Carlo (MC) simulation reproducing the kinematics of photo-hadronic
interactions at internal shocks, including the pair production process that the
secondary gamma rays undergo in the GRB jet. We find that sub-TeV observations
of GRB 190114C can be reproduced by a baryonic energy content comparable to
that in sub-GeV photons and a bulk Lorentz factor $\Gamma=100$, with a ms
variability timescale. Neutrino flux predictions by the model are found to be
consistent with experimental upper limits set by ANTARES and IceCube.
