Not sure if I trust they're info.
The kicker is getting the nuke down hole past the BOP, If they can do that then they can run a packer and if they can do that then they can plug this thing and not need to try anything as dangerous as firing off a nuke downhole.
According to this Russian propaganda film, a shaft was drilled at an angle near the original pipe and the nuke was put into the new shaft. Start at about 16 seconds into the film to skip some sillyness.