getting a few python packages onto the jetson-nano (or most anything with a Debian-style linux, for example a raspberry pi) without an internet connection.

Assuming another Debian or Debian-derived linux box (ubuntu or raspbian) that does have an internet connection.

On the machine with an internet connection

First, download the python-pip packages. for both python 2 and python 3: 

apt-get download python-pip python3-pip

two files should be downloaded (check with ls): 

python-pip_9.0.1-2.3~ubuntu1.18.04.1_all.deb
python3-pip_9.0.1-2.3~ubuntu1.18.04.1_all.deb

These are native ubuntu '.deb' packages. Copy them to the usb stick.

Next, download the python packages we need, using pip: 

pip download imutils
pip download pynetworktables

pynetworktables depends on another package called monotonic, so there should be 3 more files: 

imutils-0.5.3.tar.gz
monotonic-1.5-py2.py3-none-any.whl
pynetworktables-2018.2.1-py2.py3-none-any.whl

copy them to the usb stick too.

On the Nano without Internet

move the usb stick to the nano; copy all of those files above to a folder called for example download/cv-tools

First, we have to install pip: 

sudo dpkg -i download/cv-tools/python-pip_9.0.1-2.3~ubuntu1.18.04.1_all.deb
sudo dpkg -i download/cv-tools/python3-pip_9.0.1-2.3~ubuntu1.18.04.1_all.deb

Next, install those python packages, using the pip command htat we just installed, but running these commands: 

cd download
pip install imutils --no-index --find-links cv-tools/
pip install pynetworktables --no-index --find-links cv-tools/

The options “–no-index –find-links cv-tools/” tell pip not to use the internet for the package index and to download stuff, but to use only what's in the cv-tools directory.

After that, I can run our python opencv script without crashing due to missing packages.