The .NET IRIS dll files and nupkg files are located in the installation directory, in the dev folder. For containers, that would be /usr/irissys/dev/dotnet/bin. 
Source: https://docs.intersystems.com/components/csp/docbook/DocBook.UI.Page.cls... 

Install Docker Engine on Ubuntu: https://docs.docker.com/engine/install/ubuntu/ 

I've found Docker's documentation to be the most reliable. There are also instructions for Debian, RHEL, Fedora, etc.
 

The intersystems-iris-native module for node.js can be found within the Intersystems installation directory. Specifically, it is in: isc-install-dir\dev\nodejs\intersystems-iris-native\
Basically, you can copy the module from the InterSystems installation directory into your node_modules directory for your project, or install it globally.

Source: https://docs.intersystems.com/components/csp/docbook/DocBook.UI.Page.cls... 

Failing that, you can also locate the node.js driver and other drivers from: https://github.com/intersystems-community/iris-driver-distribution