Sure! This is the report: https://unece.org/sites/default/files/2022-04/LCA_3_FINAL%20March%202022.pdf

It has a description of the methods and the ISO standards they use to determine life-cycle CO2, from the cradle to the grave numbers. It also includes all the references and sources. I'm sure there's a lot more info available about the research they did, but this is the high-level report.

The UN seems like a pretty reliable source and the report seems very thorough, but I'm not qualified to say where they went wrong. So I would love to see what other sources say on the subject.

Edit: They even state in their report why the value they give for nuclear is on the low end of most accepted literature:

This value is comparable to the lower range of literature values because of the following assumptions: revised energy inputs for mining and milling, including electricity inputs for ISL, centrifugation-only enrichment, longer lifetime assumed for nuclear power plant (60 years instead of 40).

But even if you double the amount, it's still the best or at least one of the best.