Based on the experimental data of total, nonelastic, elastic cross sections and elastic-scattering angular distributions for n + 58Ni reactions, a set of neutron optical model potential parameters is obtained in the region of incident neutron energy from 0.8 to 150 MeV. Then the reaction cross sections, angular distributions, energy spectra, gamma-ray production cross sections, and gamma-ray production energy spectra are calculated and evaluated by optical model, distorted wave Born approximation theory, Hauser-Feshbach theory, exciton model, and cascade mechanism inside nuclear. The results are compared with existing experimental data and other evaluated data from ENDF/B-VI and in agreement with each other within the uncertainties of these evaluations and measurements. Finally, the covariances for the important neutron cross sections are estimated using the SPC code based on the available experimental data.