NATO is not an entity making policy or laws, their parliamentary assembly declared Russia terroristic a few days ago. No actual consequences.

Even if multiple nations would do it, nothing might change. Many countries might have no legal mechanism to enforce such statement or designation.

What people and Ukraine are on about is the US. If their Congress declares country terrorist, it will bring in those secondary countries being punished and all business with Russia ceasing due to American law. Especially since a lot of global trade is tied to American IT.

But that's when the US does it. Not EU, NATO or X European country.