/usr/alpha-linux-gnu/lib/libnsl.so is in libc6.1-dev-alpha-cross 2.23-0ubuntu3cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/alpha-linux-gnu/lib/libnsl.so.1.1
/usr/alpha-linux-gnu/lib/libnsl.so.1.1