The calculated distance (air line) between Al Başrah al Qadīmah and Nasiriyah is approximately 100 miles respectively 161 kilometers.
By car or train, the actual journey to Nasiriyah is certainly longer, as only the direct route (as the crow flies) between Al Başrah al Qadīmah and Nasiriyah has been calculated here.
Air line (approximately)
161 kilometers
87 nautical miles