CO2 per kWh is lower for nuclear (12g/kWh) than it is for solar (41g/kWh):

https://www.solar.com/learn/what-is-the-carbon-footprint-of-...

That link is also using an average including older reactors that require more highly enriched uranium (enrichment is energy-intensive), newer designs that can run on natural or low enrichment uranium can do 1.31g/kWh:

https://www.frontiersin.org/journals/energy-research/article...