The calculated distance (air line) between Nablus and Dayr al Balaḩ is approximately 77 miles respectively 124 kilometers.
By car or train, the actual journey to Dayr al Balaḩ is certainly longer, as only the direct route (as the crow flies) between Nablus and Dayr al Balaḩ has been calculated here.
Air line (approximately)
124 kilometers
67 nautical miles