Sixty-eight meters is just a shade over 223 feet. Very few nukes would fit into that machine.
The general unclassified thought from a number of sources is that the submarine has several larger torpedo tubes, through which Israeli nuclear-armed cruise missiles can be launched.
I am thinking Israeli SEAL team, a few sleds and a cadre of explosives which includes some nukes.
Just a quick look at various specs, and its armament consists of 16 torpedoes/missiles.