The calculated distance (air line) between Mariinskiy Posad and Nizhniy Novgorod is approximately 144 miles respectively 231 kilometers.
By car or train, the actual journey to Nizhniy Novgorod is certainly longer, as only the direct route (as the crow flies) between Mariinskiy Posad and Nizhniy Novgorod has been calculated here.
Air line (approximately)
231 kilometers
125 nautical miles