It is cut in half by the pager. You can pipe/redirect it or use --no-pager to get the whole contents.
Based on what I can see, it looks like you were originally using /home/phatle/NixOS and are now using /etc/nixos. Which user owns /etc/nixos? I suspect the error you are getting is repository path is not owned by current user. If so you have options, namely marking the directory safe in your git config.