First of all I must say that there are zero resources because Greek official policy was that Greece did not have nuclear weapons. There were widespread rumours of nuclear artillery being activated in Greexe in 1962 and Araxos air base was indeed certified as capable of servicing aircraft modified for nuclear delivery. Although to be clear Greece acquired A7 Corsair in 1974, after the Turkish invasion and there is no evidence that it was modified to be nuclear capable.

I understand that this is not neccessarily up to the level that the sub requires but I cannot fathom a way to prove a negative statement.

If there had been any kind of an attempt, it would have surfaced in the past 50 years and there is zero evidence of Greece ever risking to provoke the full blooded wrath of the Americans attempting to take american nuclear bombs. Both zero in Greek bibliography+press but also there is not a single mention in declassified CIA documents.