One that works really well for me is start krugs, then go raptors, then go red (use smite on krugs & on red). At this point you either take crab or continue wolves, blue, gromp. Make sure to keep farming in between ganks, contrary to popular belief Nocturne has fairly strong ganks pre-6 as well as post-6
skill order: lvl 1 q, lvl 2 w, lvl 3 q, lvl 4 e, then max R>Q>E>W
An example build for Noc would be:
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/
. But Noc has a lot of variety in his build options.
If you want you can make an euw acc to pm me, I can record some of my games and/or coach you. I've mained Nocturne before, and while I'm not that good (I'm only plat V) I do have a lot of experience both playing as, and with, Nocturne. I could go a bit more in-depth in regards to builds etc. there.
I go by Dar Raksada on EUW.