I think you're being sarcastic but exactly! It basically worked for North Korea and I bet Ukraine wishes they held onto theirs these days. But idk if even something as powerful as a nuke is needed, you just need some measure that makes attacking the place less valuable than not. Personally, that screams cyberwarfare to me (e.g. yeah you can take our city but by the time you do I will have shut down your electric grid and financial market for a few days) but who knows