Begin by installing Termux. Then, install Go:
pkg install golang
Now, download NNCP. For instance:
curl -O https://nncp.mirrors.quux.org/download/nncp-8.7.0.tar.xz
Find more recent releases at the NNCP tarballs page. Also, at this point it would be good to verify the signature and sha256sum.
Now, unpack it:
tar -xvf nncp-8.7.0.tar.xz
Now, compile and install:
cd nncp-8.7.0 PREFIX=$HOME/nncp ./contrib/do install
Now, NNCP is installed in $HOME/nncp. You may wish to add $HOME/nncp/bin to your $PATH.
Links to this note
Termux is a package that brings several things to Android:
NNCP lets you securely send files, or request remote execution, between systems. It uses asynchronous communication, so the source and destination need never be online simultaneously. NNCP can route requests via intermediate devices – other NNCP nodes, USB sticks, tapes, radios, phones, cloud services, whatever – leading to a network that is highly resilient and flexible. NNCP makes it much easier to communicate with devices that lack Internet connectivity, or have poor Internet.