The Essential Docs, to get started quickly.

1) Here's what you'll need to deploy your program. 
Choose a target platform:
[Windows] [Linux] [Mac] [Android] [iPhone] [Web] [Web+Wasm] [Haiku] [Genode] [Nintendo Switch]

Note: Instructions for cross compilation are here.
(only these combinations work: ...)

2) Set up your environment, our recommendation. Please choose a platform: 
...

3) Interacting with the compiler, basic instructions.

4) Writing a basic library, source control, unit tests, and IDE tips

5) Getting a skeleton program up and running, and using that library.
Please choose the kind of program you're developing: 
(Links provide libraries you'll need, and guide you to a deployable skeleton app)
- A command line tool.
- A portable GUI desktop app
- a GUI app for a specific platform
- A 2D Game
- A Web application or website
- An android mobile app
- An iPhone mobile app
- a library
- Other? leave feedback to let us know what we're missing.

5.5) Recommended workflows, ways to avoid complexity, and general advice for writing software well from veteran Nim users.

6) Language basics. 
- These are wonderful tutorials: ... links...

7) Language at a glance, Nim from the mainstream language you know:
- Nim for the python programmer
- Nim for the C programmer
- Nim for the C# programmer
- Nim for the Javascript cowboy
- ... add more at our leisure.

Related: Also explain support for different paradigms in Nim. (procedural, OOP, functional)

8) Use Cases: How to do X in Nim? (by topic)
- Show Nim packages and std lib, Maybe in reference to other language capabilities, or even compared to their samples.
- Be honest if there are some holes, chance to show interop with python and nimgen+c2nim.

9) To learn more about Nim's features and how to use them, please refer to the official tutorial Part1, Part2, and the Manual.