And, of course, there's making massive amounts of the environment radioactive.
I've never read that. It's easy enough to do, but the (planned) usage of these weapons (outside of hitting the enemy's heavily hardened targets on the ground) tends to rely on airbursts.
I don't remember either side relying on nuclear winter strategically. The logic of MAD is terrible enough to serve as a deterrent even without maximizing dust in the atmosphere. I remember the disarmament advocates warning of nuclear winter, and the warmongery types minimizing its liklihood.
As to how much any world power has actually strategized and mobilized resources toward such an end (deliberate global suicide that destroys both sides by design) is likely to never be fully revealed, since it's a slightly alarming idea.
Even so, some of the plans that have been revealed really are quite terrible. Bad enough, that the difference between deliberate and accidental nuclear winters could be considered an argument that splits hairs.