Nocturne is a REALLY UNIQUE and interesting Toplane champ if you want to play him successfully in high elo! With THIS BUILD (copied from Korean 1100LP Challenger Nocturne OTP) you have a very special Powercurve fitting COMPLETELY DIFFERENT ROLES throughout different points of the game.

Early (Levels 1-5) you are a SUPER STRONG 1v1 Duelist

Once you get Lv.6 and Tiamat you suddently become an INSANE Roaming/Proxy Champ who deletes waves with 1 Auto-Attack and kills Turrets as fast as Fiora/Trundle

Midgame (1-2 Items) you are a mix of Longrange Engager/Tank/Assasin, catching off anyone who oversteps their welcome on sidelane/jungle

Lategame (3+ Items) you are a low-medium Dmg TANK, who still has enough damage to make the enemy ADCs (or immobile Mage Carrys) life PURE MISERY. Every fight YOU, with your 4k HP + Stridebreaker + Frozen Heart + Zekes (later on) will fly in their face deal about half to all of their HP in dmg and then walk/flash out, while your team already won the fight/will follow up and win it from there

He often finishes his build with Serpants even if the only shield is a Barrier on the ADC because:
1. It lets you sell Dblade without losing Jack Stacks because of the Lethality
2. Your build relys mainly on your base damages so Serpants flat reducing all shields has no scaling + the lethality amplyfies your base damages

One of the Runes, which the OTP uses EVERY GAME is Jack of All Traits. Which grants bonus ad and haste at 5 or 10 unique stats from items.
Nocturne can achieve this exeptionally well with just DBlade + Mercs + Stridebreaker + Frozen Heart. At 2 Items + Boots he gets an extra 25 adaptive Force (15 AD) + 10 Haste
15 AD = 525 Gold 10 Haste = 500 Gold.
So you get a total of 1025 GOLD in Stats just from this one Rune at full stacks

ALSO you get 460 Gold (6 AD 5 Haste) in Stats at 5 Stacks
This can be achieved with DBlade + 2 of: Boots/Armor/Dagger (good in harder lanes)

With Tabis you dont quite get it at Stride + Frozen Heart you need to buy full Spectre's Cowl(1250g & builds into Kaenic) to get to 10 unique Stats

Nocturne is a very team-oriented pick, its not as much about dominating the 1v1 past lv.6 if you play with bad teammates it can be hard to solo match very strong splitpush scalers such as Garen Fiora as they will ALWAYS outscale you in the 1v1 at SOME point. Also, with this Pick you will VERY OFTEN have negative KDA
just look at the OTPs KDA https://www.onetricks.gg/de/players/Mi4wa9sn5yWDqChfFxgubyQkhlWHB0PMxPAVMa_C1WCkgBqJ4Q3ZTl6LFVBhRIGOqx9ELcCByAa0wQ
His current KDA looks like this: 4.5 / 5.3 / 6.6 with a 57% Winrate at 1100LP Chall

This does NOT seem right to many people who thing you need to play 1v9 carries to win games/climb rating.

Dont get me wrong you WILL have these games where you end up being 15/2 or something similar and feel completely 1v9, but its NOT THE NORM and its NOT NEEDED!!!

The Utility of your Ult alone gives your ADC the freedom to do their job FREELY without needing to worry about getting jumped in a coordinated attack by the enemy team (as they have 0 vision and will focus on YOU, diving into them!!)
On top of that if you have diving follow up or something like an Orianna ball on you the games are EVEN MORE FREE!!