The calculated distance (air line) between Nasiriyah and An Nu‘mānīyah is approximately 115 miles respectively 185 kilometers.
By car or train, the actual journey to An Nu‘mānīyah is certainly longer, as only the direct route (as the crow flies) between Nasiriyah and An Nu‘mānīyah has been calculated here.
Air line (approximately)
185 kilometers
100 nautical miles