Why does the removal of nuclear weapons predicate itself on countries agreeing on borders? As it stands, countries develop nuclear weapons solely because they’re afraid that nuclear weapons will be used against them (or, you’re North Korea and the West has already expended their entire sanctions repertoire to go after human rights violations and now has no recourse against nuclear weapons development).
Countries may fight over borders, but the involvement of nuclear weapons turns what should be a localized dispute into a global one with world-ending consequences.