Some quick fixes and workarounds for "chdir (/tmp/.private/nobody) failed"
Quick and Dirty Fix
chattr -a /tmp/.private chmod 1777 /tmp/.private chmod 1777 /tmp/.private/nobody chown nobody:nobody /tmp/.private/nobody
Add users to Nobody group
You may also be able to solve this by adding users to the nobody group.
usermod --groups nobody --append $user