Neuromodulation systems with nerve monitoring assemblies and associated devices, systems, and methods are disclosed herein. A neuromodulation system configured in accordance with some embodiments of the present technology can include, for example, a generator, a nerve monitoring assembly configured to detect electroneurogram (ENG) signals, and a neuromodulation catheter. The neuromodulation catheter can include an elongated shaft with a distal portion and a proximal portion. The distal portion of the shaft can include an array of electrodes configured to detect nerve activity from within a blood vessel of a human. The proximal portion of the shaft can include at least one connector that operably couples the electrodes to the generator and to the nerve monitoring assembly.