The calculated distance (air line) between Novhorod-Siverskyi and Poltava is approximately 176 miles respectively 284 kilometers.
By car or train, the actual journey to Poltava is certainly longer, as only the direct route (as the crow flies) between Novhorod-Siverskyi and Poltava has been calculated here.
Air line (approximately)
284 kilometers
153 nautical miles