In short, there is no such thing as a "local" nuclear war.
Article VI is the heart of the NPT, because it not only requires abolishing nuclear weapons but also addresses the fears that non-nuclear armed nations have about the major powers' conventional forces. A number of countries -- China in particular -- were stunned by the conventional firepower unleashed by the US in its 2003 invasion of Iraq. The ease with which US forces dispatched the Iraqi army was a sobering lesson for a lot of countries.
In part, it is the conventional power of countries like the US that fuels the drive by smaller nations to acquire nuclear weapons.
Libya is a case in point. That country voluntarily gave up its nuclear weapons program in 2003. Less than seven years later Muammar Gaddafi was overthrown by the US and NATO. At the time, the North Koreans essentially said, "we told you so."
The NPT has done a generally good job of halting proliferation. While Israel, Pakistan, India and North Korea obtained nuclear weapons -- the first three never signed the Treaty and North Korea withdrew in 2003 -- South Africa abandoned its program and other nuclear capable nations like Japan, Brazil, Argentina, Iran, South Korea and Saudi Arabia have not joined the nuclear club -- yet.
But it is hard to make a case for non-proliferation when the major nuclear powers insist on keeping their nuclear arsenals. And one can hardly blame smaller countries for considering nuclear weapons as a counterbalance to the conventional forces of more powerful nations like the US and China. If there is anything that might make Iran abandon its pledge not to build nuclear weapons, it is all the talk in Israel, the US and Saudi Arabia about regime change in Teheran.
There are specific regional problems, the solutions to which would reduce the dangers of a nuclear clash. The US has taken some steps in that direction on the Korean Peninsula by downsizing its yearly war games with South Korea and Japan. Declaring an end to the almost 70-yesr old Korean war and withdrawing some US troops from South Korea would also reduce tensions.
Halting the eastward expansion of NATO and ending military exercises on the Russian border would reduce the chances of a nuclear war in Europe.