Europe is toast. Maybe an enclave in Berlin where WARPAC and NATO forces don't want to nuke themselves? (Useful maybe for story purposes).
France and Germany are going to be radioactive. Warsaw Pact nations would have been flattened, expect high casualties both during and after war due to famine. Expect warlordism, mass starvation, the return of many old diseases and birth defects.
Britain is also likely to be in a state as most (if not all) of her major cities are hit. Maybe small provisional governments exist.
USSR is going to be glowing in the dark. It gets hit by thousands of weapons courtesy of the US, Europe (maybe China?). Expect very little surviving infrastructure or centralized government. Likely to be a land of ash, famine, death and warlordism.
The US is likely to be pretty fucked in a 1980's exchange. Many major cities will have been flattened as the Soviets target population centres, major military bases, missile installations, air force bases. Mass famine, mass death and its likely the central US government (assuming it survives) will struggle to assert its authority over the whole country. Maybe lots of smaller provisional authorities pop up.
China I believe would be hit by the USSR. Japan and Korea are likely to also be fucked. (Citation needed) Unsure about India. Likely to be hit maybe by USSR and or Pakistan?
South America I am unsure. Likely a few major cities hit, despite not really being aligned, the Soviets are likely to target nations who they think might help the US recover. Unsure, possibly the most unscathed continent.
Africa I am unsure about. Maybe South Africa cops a few hits. Continent is likely to be somewhat unscathed but the collapse of all the major powers is going to upset eveyrthing.
Australia and NZ likely to suffer a few hits, possibly the only Western nations who are going to be in some sort of shape assuming they can keep their central governments together.
Verdict: US: gone, USSR: super gone, Europe: gone, China: gone. Billions die in the initial exchange, billions more die in the ensuring two years of collapsed trade, crop failures, disease, radiation and general post-war misery.
Severe damage to the environment, global temperature drops in places (adding to the misery).