nnunet is still not fixed. If anyone comes across this issue, the current workaround is to open Slicer’s Python console (Ctrl+3) and type this command:
pip_install("acvl_utils==0.2")
I’ve pushed a fix (a temporary workaround) to the Slicer TotalSegmentator extension that automatically gets a working acvl_utils package version. This will fix the problem for all new Slicer installations from tomorrow.