Hello and welcome to my guide on how I play nocturne i dont this is what works for me and if it dosent work for you that aint my problem so dont leave a comment saying this guide sucks thank you and i hope this guide helps you :)

TAKE THE PURE AD YELLOW RUNES NOT AD PER LEVEL RUNES

follow the verry specific item list item by item (dont forget to pick up some pots on the way)
untill you get to the frozen mallet at this point in the game sell your boots for the mallet you dont need them anymore as your dancers will keep you up to speed and your mallet will slow people preventing any escape untill then i recomend a red buff at all times and a blue buff to for no mana problems, after you have that you sell your exicutonar's calling for your first bloodthirster and then your cloak and dagger for the second you will need to buy potions at then end and you will have 95% crit chance :) with 260% crit dmg you will be hitting like a truck with 500 ad while on your dusk trail and 50% lifesteal comind with your mallet for chasing you will be unstopable at this point in the game

try and lane with a char that has a reliable snare/slow/stun (reliable meaning non skillshot or some1 who is good at skillshots) and you will be getting the kills left and right

simple cheap runes that will make you hit hard early game.

flash and exhaust you could swap flash out for ghost if you like but exhaust is an nessesety for any ad melee.

well this is the guide i may add onto it later or tweak a few things hope this helps you alot goodbye and goodluck on the fields of justice