Gah! One of their reports within the past 5+ years. It was in an analysis of risks by major energy modalities. Unfortunately IPCC's content organisation is a disaster.
Analysis unit was deaths per GWh or similar.
I'll see if I can find it though I'm not optimistic.
Our World In Data posts similar stats, premature deaths/yr at 1 TWe/yr generation:
Coal: 25
Oil: 18
Gas: 3
For the safer options, statement is inverted, as
years for 1 death:
Nuclear: 14--100
Wind: 29 years
Hydropower or solar: 42 years
Solar: 53
Note w/h/s are all within the range of error for nuclear. (And why hydro isn't broken out separately I don't know.)
https://ourworldindata.org/safest-sources-of-energy