Uh, I suspect we do not have enough nuke subs active and deployed.
We have SSBNs on deterrent patrol, and in range of all designated target packages at all times, and this has been true continuously for the last 50 years.
And "one" is enough.
A Trident SSBN could destroy North Korea from its homeport.
You’d be quite “underestimative” about that. The USS Ohio operates regularly out of Bangor and it alone could re-configure NKor. But the Ohio has a whole quiver full of friends, both boomers and fast attacks with vert-tubes that also operate from Puget Sound and Pearl. Then don’t forget the USS Nimitz is on its way and it has underwater friends who can bite if called upon by the Kenyan.