Dissociation of the nitrogen molecule via plasmon-enhanced catalysis using noble metal nanoparticles has been investigated both experimentally and computationally in recent years. However, the mechanism of plasmon-enhanced nitrogen dissociation is still not very clear. In this work, we apply theoretical approaches to examine the dissociation of a nitrogen molecule on atomically thin Agn nanowires (n = 6, 8, 10, 12) and a Ag19+ nanorod. Ehrenfest dynamics provides information about the motion of nuclei during the dynamics process and real-time TDDFT calculations show the electronic transitions and population of electrons over the first 10 s of fs time scale. The activation and dissociation of nitrogen are typically enhanced when the electric field strength increases. However, the enhancement is not always monotonic with field strength. As the length of the Ag wire increases, nitrogen is typically easier to dissociate and thus requires lower field strengths, even though the plasmon frequency is lower. The Ag19+ nanorod leads to faster dissociation of N2 than the atomically thin nanowires. Overall, our detailed study yields insights into the mechanisms involved in plasmon-enhanced N2 dissociation, as well as provides information about factors that can be used to improve adsorbate activation.