Would nuclear power tunnel borers be good delivery systems for nukes?

Aright, so suppose I got the figures in my specific, demonstrative hypothetical example wrong. even assuming they tunnel in a straight line that still makes, what, four months, not counting the 4km DMZ itself,. the central point still stands that, unelss a neutral Austria wants to surprise-nuke an unsuspecting, technologically-regressed Bratislava or something, it's quite a stupid option, especially if there are better options available.

I was just fixing your math. Also OP is clearly talking about a retaliation weapon that hits decades even centuries after it starts, and carries a nuke large enough to move tectonic plates.

IMO I disagree with OP, if you can tunnel bore as a weapon of war it would be better to deliver troops with it, than nukes. Or make bunkers.