The calculated distance (air line) between Sergach and Nizhniy Novgorod is approximately 79 miles respectively 127 kilometers.
By car or train, the actual journey to Nizhniy Novgorod is certainly longer, as only the direct route (as the crow flies) between Sergach and Nizhniy Novgorod has been calculated here.
Air line (approximately)
127 kilometers
69 nautical miles