This is huge, and confusing. Poland doesn't have any nuclear reactors, or nuclear expertise of any kind. The latency to obtain nuclear weapons—unless some allied country literally gifts them—would presumably be extremely long. AFAIK it also doesn't have long-range missiles, nor any missile industry: hence no credible, modern delivery mechanism.

Poland is a signatory of the international nonproliferation treaty, although that's merely symbolic because anyone can exit with just 90 days' notice[0].

Less symbolically, Poland has a Section 123 treaty agreement with the United States[1], which obligates nonproliferation and is tied to literally tens of billions[2] in ongoing commercial nuclear power investments. Granted that in the current political climate, anything could happen; during the ancien régime, this action would (I understand) have triggered automatic US sanctions on nuclear technology—something that'd be stupidly expensive with the amount of nuclear reactors Poland is currently buying from the USA (and from Korea, another 123 signatory).

[0] https://en.wikipedia.org/wiki/Treaty_on_the_Non-Proliferatio...

[1] https://www.energy.gov/nnsa/123-agreements-peaceful-cooperat...

[2] https://en.wikipedia.org/wiki/Nuclear_power_reactors_in_Euro...