We perform a first-principle calculation of optical potentials for nucleon
elastic scattering off medium-mass isotopes. Fully based on a saturating chiral
Hamiltonian, the optical potentials are derived by folding nuclear density
distributions computed with ab initio self-consistent Green's function theory
with a nucleon-nucleon t matrix computed with a consistent chiral
interaction. The dependence on the folding interaction as well as the
convergence of the target densities are investigated. Numerical results are
presented and discussed for differential cross sections and analyzing powers,
with focus on elastic proton scattering off Calcium and Nickel isotopes. Our
optical potentials generally show a remarkable agreement with the available
experimental data for laboratory energies in the range 65-200 MeV. We study the
evolution of the scattering observables with increasing proton-neutron
asymmetry by computing theoretical predictions of the cross section and
analyzing power over the Calcium and Nickel isotopic chains