The calculated distance (air line) between Irtyshsk and Nizhnyaya Omka is approximately 147 miles respectively 236 kilometers.
By car or train, the actual journey to Nizhnyaya Omka is certainly longer, as only the direct route (as the crow flies) between Irtyshsk and Nizhnyaya Omka has been calculated here.
Air line (approximately)
236 kilometers
127 nautical miles