I too struggled a bit with this also. Here is a solution that worked for me, courtesy of https://elinux.org/Jetson/Remote_Access
#!/bin/sh
# Share one network's internet connection with another network.
# eg: If your Wifi adapter with internet is called wlan0
# and your local Ethernet adapter is called eth0,
# then run:
# ./share_my_internet.sh wlan0 eth0
# This will only last until you reboot your computer.
sudo iptables --flush
sudo iptables --table nat --flush
sudo iptables --delete-chain
sudo iptables --table nat --delete-chain
sudo iptables --table nat --append POSTROUTING --out-interface $1 -j MASQUERADE
sudo iptables --append FORWARD --in-interface $2 -j ACCEPT
sudo sysctl -w net.ipv4.ip_forward=1
chmod +x share_my_internet.sh
Run by
./share_my_internet.sh <Host's internet interface name> <Host's nano's usb interface>
For me that’s sharing laptops wifi = wlp4s0 to usb interface enp0s20u3