The calculated distance (air line) between Kozlovka and Nizhniy Novgorod is approximately 167 miles respectively 269 kilometers.
By car or train, the actual journey to Nizhniy Novgorod is certainly longer, as only the direct route (as the crow flies) between Kozlovka and Nizhniy Novgorod has been calculated here.
Air line (approximately)
269 kilometers
145 nautical miles