Using first‐principles quantum mechanical calculations, we investigate the electric field amplification in hybrid nanostructures composed of few‐atom Ni linear chains attached to an organic molecule. We found that the pristine Ni linear chains exhibit localized plasmons and produce nanoscale hotspot regions, acting as a plasmon‐like nanoantenna. We demonstrate that localized plasmons provide massive electric field amplification in the vicinity of the molecule. Besides, we also investigated the active modulation of the optical absorption spectra due to the inclusion of a positive and/or negative electric field in the Hamiltonian. We believe that the results presented in this work are important for the emerging field of cavity induced photo‐catalysis and will aid in the realization of new quantum nano‐optic devices.