The calculated distance (air line) between Gavrilov-Yam and Nizhniy Novgorod is approximately 171 miles respectively 275 kilometers.
By car or train, the actual journey to Nizhniy Novgorod is certainly longer, as only the direct route (as the crow flies) between Gavrilov-Yam and Nizhniy Novgorod has been calculated here.
Air line (approximately)
275 kilometers
148 nautical miles