Core electron binding energies (CEBE) of nickel and copper atoms have been calculated using single‐configuration energy differences, the so‐called Δ‐self‐consistent field (Δ‐SCF) method. Basis set convergence has been examined for calculated L‐shell and M‐shell core electron binding energies, and a wide array of density functionals have been evaluated. Scalar relativistic corrections have been estimated using the popular Douglas‐Kroll‐Hess (DKH) approximation. While basis set convergence and functional dependence mirror the behavior reported in the literature for main group elements, the simplest Δ‐SCF calculations with pure Hartree‐Fock (HF) exchange and no correlation surprisingly outperform all density functionals in reproducing free‐atom CEBE values for Ni and Cu.