brew install nats-server

.../...
==> Pouring nats-server--2.9.14.arm64_monterey.
==> Caveats
To restart nats-server after an upgrade:
  brew services restart nats-server
Or, if you don't want/need a background service you can just run:
  /Users/user/brew/opt/nats-server/bin/nats-server
==> Summary
🍺  /Users/user/brew/Cellar/nats-server/2.9.14: 8 files, 11.3MB
==> Running `brew cleanup nats-server`...

See also

• NATS Messaging, installation, Install NATS using docker, nats server check, nats-server.conf, nats.ws, 4222, Synadia, Synadia Cloud, NATS JetStream, Terraform provider, Leaf Nodes