I had been thinking of the AIR-2 Genie a nuclear missile, being used as an anti-aircraft weapon against potentially nuclear armed Soviet bomber formations. As a person of the 21st century I have serious misgivings about the idea of detonating nuclear weapons near other nuclear weapons, but am curious if this sort feeling was contemporary with these sorts of weapons, or if I am anachronistically projecting current feelings about nuclear weapons onto a different era.
The odds of one nuclear weapon setting off another nuclear weapon successfully are very low. For technical reasons, if you set off a nuke near another nuke you are likely to disable the other nuke, not set it off. So the fear of setting off other nukes with nukes was not really a serious one — the more serious fear was disabling your own nukes with other nukes you were firing (if you fired three nukes at the same target, you had to time them so the first one didn't break the other two), what is known as "nuclear fratricide."
With anti-aircraft nukes like the Genie, there were always some concerns that setting off nukes over your own territory would create collateral damage against your own people. But you have to remember that the goal of a weapon like the Genie was to use a tiny nuke to destroy a bomber carrying a much larger nuke, a bomber that was intending to drop it on a city or military target. So the rationale was that while such anti-bomber warfare might create collateral damage it was probably better than letting the bomber do what it was intending to do.