Who would blink first?
It is a common assumption that the Soviets would be the first to make use of tactical and sub-strategic nuclear weapons, yet as I pointed out above, historiography indicates otherwise.
it appears that the Soviet leadership expected that the US and NATO (near simultaneously) would be the aggressors. This was backed up by debrief reports from defectors (eg Oleg Gordievsky in the early 1980s) and the sheer US overage of tactical nuclear weapons (8:1 overage) and strategic weapons (c 6:1) in the mid 1960s. (see Marc Trachtenberg's 'A Constructed Peace').
The 1968 NPT was effective in stopping state-led proliferation (except, as it happens North Korea) and the 1972 ABM treaty between the US and Russia delayed deployment of ABM systems by about 5 years. SALT I and SALT II did impose practical limitations on strategic nuclear weapons in the 1970s and 80s (respectively) but each of these well-meaning gestures were scuppered by peripheral conflicts such as Angola, Nicuaragua, Afghanistan etc.
Technical advances - such as reducing both yields and the CEsP meant that by the 1970s, the crude and inflexible function of the deterrent gave leaders fresh options and thus lowered the 'nuclear threshold'.
The worry of senior politicians (eg Sir Geoffrey Howe) and the security services was a mis-reading of intentions. Thus Soviet (and a lesser extent US) paranoia conflated with a range of 'precise' tactical weapons could have resulted in a 'pre-emptive' strike by USSR (in the correct legal sense) as they believed that NATO was about to attack them. This came to a head during the NATO CPX ABLE ARCHER in 1983, when the "Centre" under terminal-ill Andropov issued bizarre instructions to its Rezidentz to garner information on diverse subjects as late-night working in government buildings, increase collections at blood-banks, and the flight of bankers and clerics to 'safe' areas. (See Chris Andrew's tome Defence of the Realm pp 720 et seq).
Soviet target set information was briefly available in the mid 1990s however archives are well and truely locked down now, although some Western historians managed to gain access, such as Haslam. The theft of KGB archives by Mitroyken in c 1991 also give an indication that Russian J2 was sadly lacking, with long-closed facilities and infrastructure being targetted by Spetznaz and by tactical weapons - conventional and nuclear.
So, in sum, we could have expected some troop concentration areas and airfields being targetted by tactical nuclear weapons - but targetted doesn't always equate to be hit. The Russians had major problems with guidance and fusing systems - partly because of the fear of engineers and technicians to report problems and faults with systems. Now imagine you are on TACEVAL and your IED inject is a Soviet UXN...'Cordon Party: establish a safe perimeter of, oh, 10 miles...'