The calculated distance (air line) between Hiroshima and Nishinomiya-hama is approximately 165 miles respectively 266 kilometers.
By car or train, the actual journey to Nishinomiya-hama is certainly longer, as only the direct route (as the crow flies) between Hiroshima and Nishinomiya-hama has been calculated here.
Air line (approximately)
266 kilometers
144 nautical miles