A nickel/blue light-catalyzed carbohalogenation reaction is reported. A nickel catalyst and an inexpensive phosphine ligand promote the reaction of aryl iodides and aryl bromides with π systems to enable the construction of a library of halogenated heterocyclic scaffolds. Mechanistic studies provide insight regarding fundamental steps of the catalytic cycle, including the reversible C−X bond formation via deuterium labeling and EPR experiments, while preliminary enantioselective results suggest a two-electron migratory insertion.