South Korea and Taiwan could as well in short order.
So could Canada and Brazil, although it would take the latter longer, but they do have the basic technology and infrastructure to restart their nuclear weapons program.
Japan could have a nuclear weapon tomorrow if they wanted to. They have the complete technical expertise and more than enough plutonium to build nuclear weapons quickly. It would not be a surprise if they already have designs and plans for one, should they decide it is necessary to do so. Their Epsilon rocket could quickly be converted to an ICBM.
"If you will not fight for right when you can easily win without blood shed; if you will not fight when your victory is sure and not too costly; you may come to the moment when you will have to fight with all the odds against you and only a precarious chance of survival. There may even be a worse case. You may have to fight when there is no hope of victory, because it is better to perish than to live as slaves." - Sir Winston Churchill