# install gparted
nix-shell -p gparted

sudo gparted

# Use gui to create partition and format and label 'data'

# Make directory to mount created partition 
mkdir -p /mnt/data

# Mount partition of device to /mnt/data mount point
mount dev/???????  /mnt/data

-----------------
Nixos-generate-config

replace (backup)
ul.1.goodg.org/ncbc/ne###/hardware-configuration.nix 

on ~
sudo sh u_nix.sh 
 - if not there,  wget https://ul.1.goodg.org/ncbc/ne###/u_nix.sh
 - this will  ultimately run 'nixos-rebuild switch
 
sudo reboot