The calculated distance (air line) between Nakło nad Notecią and Częstochowa is approximately 175 miles respectively 281 kilometers.
By car or train, the actual journey to Częstochowa is certainly longer, as only the direct route (as the crow flies) between Nakło nad Notecią and Częstochowa has been calculated here.
Air line (approximately)
281 kilometers
152 nautical miles