Missing icon in the settings for the "Power Line Type" - one of the options in drop down list reads [item=nullius-nickel-wire] Bare Nickel

I have Nullius & Lambent Nil installed, but without the Tricky Old Nick one.

See https://imgur.com/a/3Ho7ERT

Right, that setting is mostly meant for people who are playing with Tricky Old nick installed, but nothing about it inherently requires that mod to be installed besides that icon. I'll see about making it use a fallback icon just to prevent the strange looking text in the next update.