It is interesting to think about what kinds of warheads were available to NATO in the 4th ed. version of the Twilight War.
Historically (i.e., real history with the USSR collapsing and no Twilight War), the United States almost entirely phased out tactical nuclear weapons in the early 1990s. This began with the Presidential Nuclear Initiatives of 1991, which called for the withdrawal and dismantlement of all ground-based and sea-based tactical nuclear weapons, consisting of 155mm and 203mm artillery shells, Lance and sea-launched Tomahawk (TLAM-N) missile warheads, and nuclear depth bombs. (Contrary to some popular beliefs, the United States did not possess nuclear torpedoes at this time.) Additionally, nuclear bombs were removed from aircraft carriers. Keep in mind intermediate-range nuclear forces (Pershings and ground-launched Tomahawks) had previously been withdrawn under the INF Treaty.
The United States' decision to phase out these classes of weapon immediately affected NATO countries that participated in nuclear sharing, since their artillery and tactical missile warheads were provided under dual-key arrangements.
The only tactical weapons left ready to use were air-delivered bombs, some of which remained forward-deployed for NATO missions, including nuclear sharing, and are retained for this purpose today. In addition, it appears the TLAM-N may have been retained in storage as late as 2013. An idea that was discussed at the time was using Trident submarine-launched ballistic missiles in a sub-strategic role; however, the warhead yields were too great for what we tend to think of as tactical use.
Keep in mind the strategic arsenal of intercontinental ballistic missiles, submarine-launched ballistic missiles, bombs, and air-launched cruise missiles was not directly affected. Not directly related to this, the USAF retired the SRAM nuclear missile in 1993 over safety concerns but continued to operate the ALCM.
In the 1st and 2d ed. timelines, the near-abandonment of tactical nuclear weapons probably doesn't happen (and in 1st ed. it's questionable whether the INF Treaty would have been made).
In the 4th ed. timeline, it probably does since there are a few years during which it looks like the Cold War is over and the United States government had been very eager to get rid of these classes of weapon. Most likely at the time things heated back up many of the warheads had not been dismantled or could be reassembled.
In 4th ed., France is an enthusiastic participant in the Twilight War. France did not participate in NATO nuclear sharing and had its own tactical warheads and delivery systems including the Hades tactical missile. As far as I know, France never fielded nuclear artillery shells. Historically, France's nuclear posture was not revised until 1996.