Bot threads, Ninjask and Shedinja, say the whole prevo set thing. I would guess ninjask because it’s the actual evolution, where Shedinja just comes with it. I was just wondering this.
If the Nincada set is for LC, you or someone else can make an LC thread following the required format and post sets there. If it's for a format other than LC, you would ideally put it on both Ninjask's and Shedinja's threads.
Hope I helped!