Btw, although you don't have to use the BY-NC license (you would have to manually add it through the "Create a custom license" link when you edit the mod info or submit a new mod), you can't change it to MIT (the default on the Factorio mod portal) due to the NC (Non-Commercial) requirement, which MIT license does not prevent.

Any license you set needs to have the same Non Commercial restriction at the bare minimum, because otherwise, people could find your mod, see the MIT license, and think they can fork it and monetize the code (because MIT allows that).

It's not that important for this specific mod (because it barely had any code to begin with), but it's also not that difficult to fix, and kind of important to note when forking other people's work moving forward.

You can add the custom license with these options: