/lib/x86_64-linux-gnu/libnih.so is in libnih-dev 1.0.3-4ubuntu25.
This file is owned by root:root, with mode 0o777.
It is a symlink to /lib/x86_64-linux-gnu/libnih.so.1.0.0
/lib/x86_64-linux-gnu/libnih.so.1.0.0