You might be right on the minor local point that we would still have a climate problem if the US went all-in on nuclear, but it would be a lot easier to get the US to pass border adjustments (“carbon tariffs” if you will) on China or whomever if our emissions were in good shape. We wouldn’t have a fossil fuel industry lobbying hard to preserve pollution and there wouldn’t be as much pearl clutching about the effects of the economy. Moreover, if we had 70 years of investment in nuclear, we would probably be able to quickly and cheaply stamp out safe, cost effective nuclear power plants all over the world (think about how much progress on SMRs could have been made in the same amount of time). Moreover, abundant, cheap energy would have almost certainly precipitated the electrification of everything from heavy industry to transportation to indoor heating/cooking/water-heating/etc (on the near-certain assumption that nuclear would be far cheaper than fossil fuels).