Well, for one, less than 60% of the world's total population would live in the southern hemisphere like right now. The fallout was, as we know, on horrific levels - I won't even go into the global famine that struck the world a few years after.
Second there'll be a lot more democratic governments - from the Japanese fiefdoms in the South Pacific to the notorious Boer Republic of South Africa, the world we live in only has a handful of democracies, all nominal at most. Even Papua has some problems.
It'll be a better world I guess.
Europe did fairly well in cmparison. There were increased cancer rates put down to the fallout from Western Russia of course. When the tepretures fell between 1 and 4 degrees that affected agriculture world wide. Rationing was introduced right across Europe and there were a lot of thigs we just couldn't have growing up in the 1980s. Things as basic as milk and bread were very expensive well into the 1980s after the rationing system was relaxed. It was difficult for most people but we did not experience the mass starvation seen in much of Africa and most of Asia which was really hit hard. Vietnam got more aid than most, prversely becausr of the lage scale deploymennt of the US military for the Vietnam War. Which pretty much ended after the Sino-Sviet nuclear exchnge. South and North Vietnam remaied seperate nationsand niether can be considered democracies. South Vietnam does have elections so can in rtheory be classed as democratic. But the political and econmic corruption is rampnt with power going to the party who can buy the most votes. And every few years the military take power in a coup and even this "demcracy" gets suspended for five years or so. As with the present military Junta led by General Lam.
Korea is not too differet thugh forcibly reunified in 1978 following the invsion by the US and South Korea. The military have ruled the cuntry almost permanntly apart from a brief experiment with democratic rule from 1998 - 2000. General Jong-Un is the head of the current Junta having overthrown the previous regieme of General Pak (2000 - 2012) like most South Koren military regiemes there are frequent crackdowns on food protests and democracy activists.
This is pretty typival of much of Asi.
Large parts of China remains under the conrtrol of warlords with a weak residual central government in Wuxi where the remnants of the pre war government ended up after the nuclear war Nobody considers their claims to authority maning very much at all.
The Soviet Union broke up after the exchange fallling into the bloody Second Russian Civil War 1970 - 1976. Russia itself gained a reasonable amount of stability when vladimmir Putin tok power in 2001. Uder him there has been considerable recovery. Ukraine, Georgia and the Baltic Staes graitated toward the EU. East of the Urals it is a mess. The US considered occupying parts of Siberia and did deploy troops to the coast during the late 1970s (I think it was 1976 - 1978) mostly to secure remaining Soviet nuclear weapons in the Soviet Far East after the Second |civil War and to provide humanitarin aid. The mission ws regarded as being a limited success and the area was left to he local Siberian warlords. Nobody has bothered to intervene in Siberia again.