Use .env.example as an example. Variables NODE_PEER_ALLOWED_IPS, NODE_PEER_LISTEN_PORT, NODE_PEER_PERSISTENT_KEEPALIVE, NODE_PEER_PRIVATE_KEY might stay empty for default behaviour.
Restart node
pm2 restart ecosystem.config.js --update-env
Update nginx config for node if any changes
IPFS swarm
After node is automatically set up, check for swarm peers
If you see a message, saying something about your node not being online and you don't see an api (no extension at all) file inside your IPFS folder (/ipfs/ probably), make sure you've added IPFS_PATH env variable to .bashrc and .profile and reboot your server.