Login to your new installed NanoPI with username pi password pi.
ssh pi@node1
# use same password - pi
Then continue with setup:
# setup user
sudo adduser username
# ^^ Do not forget to assign this user to sudoers.
sudo usermod -a -G sudo username
sudo usermod -a -G ssh username
# change root password
passwd
# change hostname of node. With NanoPi you can do it with utility:
sudo npi-config
# from your workstation
ssh-copy-id username@node
Next you have to assign your node fixed IP address. Make sure you write this address in file - /etc/hosts
(You can add ssh auth for easy connection) ssh-copy-id username@node1