It is funny how the same people (the nuclear lobby) who used to argue against solar due to economics (too expensive) are now arguing we should not consider economics anymore. The thing is though, at the moment most countries still produce significant portions of their elecricity from fossils. So if we want to remove them as quickly as possible, we should use the solution that gives us the highest capacity for a fixed amount of money (assuming we have only fixed funds).

Moreover because nuclear is so CAPEX driven both in cost and CO2 budget, it takes a long time to become carbon positive. So we would actually increase CO2 in the short term by building nuclear power plants.

So the best current strategy is to build up renewables to replace fossil as quick as possible, keep existing nuclear running, and develop storage. If the current trends of the cost for solar and wind continue, we might not even need much storage because building overcapacity is so cheap.