Tqdm is a simple process reporting Python package that is installed as part of nnunet. The fact that you dont have it installed,why nnunet is already installed indicates that your nnunet installation was incomplete. Nnunet installation was not included in the log file you provided, so I dont know what went wrong with it.
You can pip install tqdm manually in Slicer’s Python console (pip_install("tqdm")). If you find that then some other dependencies are missed then probably the easiest is to force reinstall the Python dependencies using the button in the advanced section.