Not quite. Chef/puppet/ansible are configuration management and server automation tools. While you could design a .nix package that describes the state of the w

Not quite. Chef/puppet/ansible are configuration management and server automation tools. While you could design a .nix package that describes the state of the whole sever that would be tedious. Ansible and nix compliment each other nicely as tools. Nix gets you highly reliable package management using principles from functional languages. Gnu guix is an alternative to Nix (the package manager).