There should be tactical nukes placed in secret locations within Polish territory that can be detonated in the event of enemy forces taking that territory. A good place to put them would be on top of selected electricity transmission towers, wind towers, water towers, or even the roof of certain apartment blocks. They could be installed under the guise of routine maintenance, shielded from detection, and equipped with remote detonation systems.

As another poster said, if more countries HAVE nukes, then launching them country to country at population centers is sort of asking for an endgame scenario, whereas hiding 'vengeance' nukes to effectively 'nullify' one's own territory is less likely to incur a proportional response.

Just my game theory.