I managed to reach Diamond EUW with a 76% Winrate playing only Sejuani and Nocturne

My opgg Link

I love "Offmeta Picks" that are hidden OP and viable in high Elo still:
Both these Picks each have a Korean OTP that is 800/950LP Korean Challenger

BOTH Sejuani and Nocturne are blindpickable champions in Toplane (which is rare enough)

Both have similar yet different playstyles that complement each other well

Both champs are INSANE for SoloQ and playing around your jungler in topside. Both Champs are really strong after 6 and there are VERY FEW games where you will not win any 2v2 Skirmishes in topside if you Pick Sejuani or Nocturne

The 2 Champs differ alot in how you want to play early levels:
Noc wants to play super aggro in MANY matchups as he is a strong duelist lv 1-3
Sejuani wants to play really passive before lv6 and only poke with W & Comet/Scorch

Nocturne gets a huge spike once he backs to get Tiamat as he can oneshot waves after and he spikes again at 5 Jack Stacks (Dorans Blade + 2 of Boots/Dagger/Armor/MR)
Sejuani Spikes with every skillpoint put into W, peaking at lv9 when W is maxed.
She also spikes incredably hard once she gets Ionian Boots as she can W -> W without losing the stacks on the opponent

Their One-Item spikes are both Insane with Stride and Liandries respectively giving huge 1v1 potential once completed

For a way more indepth guide on each go to my profile :)

Nocturne is extremely OP this season, what many dont know is that he is even more OP in Toplane.

One of Nocturnes biggest strenghts that make him a menace in higher Elos is his strong early game and his INSANE wavepush and mappresence.

Once Nocturne gets Tiamat he is able to kill the entire minion wave with 1 SINGLE AUTOATTACK. By Standing in the middle on the wave your passive applies the tiamat aoe to all minions instantly oneshotting them. With Q (extra ad and clear) and Tiamat active you can oneshot entire waves in seconds up until lategame.

If you are higher elo youll know what this allows you to do (proxy, roam, clear camps) letting you gain insane advantages without ever needing to kill you opponent 1v1

Nocturne is not reliant on winning lane so if there is a poor matchup ou can still pick him and play for roam/team/midgame

This Build goes Stride -> Fulltank for 2 Reasons.
1. Nocturne damage falls off lategame even if you build damage. So this build just lets you maximize the time you can use your HIGH base damage by making you tanky
2. Jack of All Trades: This Rune gives you about 900g in statvalue at 10 Stacks.
With Dorans Blade + Mercs + Stride + Glacial Buckler (Component of Frozen Heart), youll have 10 stacks really quickly letting you snowball even harder through early-/midgame
If you need Steelcaps(Tabis) instead of Mercs you can get
Specters Cowl (Component of Kaenic Rookern)
after Frozen Heart which will get you to 10 Stacks

You go Serpants fang if there are any Shield that will protect the enemy ADC (even just barrier)
Otherwise continue building Tank (Steraks & Zekes are good)

Sejuani can and wants to stomp the opponent in lane inbetween the levels 6-9 and snowball early skirmishes with your jungler.

If you dont manage to do so, youll still be a good tank who excells in getting picks in mid/lategame with your long Range Ult