Construction bots: if you place a blueprint for a building, if it is in construction range of a roboport, a construction bot is free, and it has the item to build it in a provider, storage, or buffer chest in the network, then a construction will go get that item and then build that building.
Moving to construction bots is transformative to the redesign and rebuild loop because you can deconstruct an entire area with a deconstruction planner and a sweep of your mouse, then paste down 6 copies of your new design with a blueprint in a few clicks and just let the bots do the grunt work, while you focus on design.
The two things that broke me out of restarting everytime I hit midgame were learning construction bots, and trying for the Lazy Bastard achievement. Since I did that, I've never felt like ending a run before rocket launch.
It's an idiom in English (in American English at least, I can't speak for the other dialects). "Nut" can be slang for a crazy person, e.g. "That guy's a real nut." Other variations are "nutters" or "nut case". A " nut" is someone who is "crazy" about that topic.