If we need radical changes fast, and nuclear can provide them(!!!) then the fact that there are some risks and that it might be a bit expensive shouldn't matter.
First of all: you say we need fast changes. That already rules out nuclear. Setting up a new reactor takes like 20 years. We don't have that time. And we wouldn't need one, each major industrial nation would need at least 100 of them, 10 billion each. There is just no way to achieve that. Not even mentioning the other downsides of nuclear.
However renewable buildup is much faster. Germany has build up more than the equivalent of one nuclear plant of solar alone in one year and the buildup speed can be easily accelerated with a fraction of the effort of trying to expand the nuclear capacity.