It's important to try new things. Nocturne top can be amazing, you can carry your team if you play it right.
Here are a few key points:
1. Don't run away once you have enough lifesteal, you'll just die.
2. You can't take on a whole team without help, be patient.
3. Be aggressive once you get 2 kills over your opponent.
4. Try and constantly be killing minions or monsters in the jungle, it will pay off.
5. Use your ult to finish a fight.
6. Ward the top of river when you are pushing early game.

Finally Nocturne can not have smite and not get yelled at for it.
I suggest using ghost for many reasons. It can get you a lot further than flash and it has a much shorter cooldown than flash. Getting away shouldn't be a problem, and ghost will be more effective if they try to flee down their own lane. Flash will work too, if you're worried about losing someone over the trees. If you want to avoid spells, you already have shroud of darkness to prevent one. So obviously you want ignite because there are too many times when it get the kill for you, even though you die. Hopefully you're not cutting it that close and you'll just use it to put down that guy who likes to run away a lot. There are a number of spells that would help win a fight, but these are the aggressive ones and that's what nocturne likes.

The items you'll need will not be the normal ones you'd expect. Most like to get some sort of mana regen and such, but we won't need those today. We will be relying on pure damage most of the time. You want to start with a long sword, the 10 damage won't be super awesome, but it will allow you to build Tiamat or Vampiric Scythe faster. Sight wards are my preference because usually you can keep healing yourself with your passive as you need to. It's more likely you'll be ganked from the jungle than die just from being pushed back. You can use your turret space to keep from being targeted and it will buy you more health as you are able to freely attack minions. Also, not pushing means you won't really need boots just yet. So farm the minions and then pick up a tiamat if you got a lucky champion kill or two already, this will let you hit all minions at once and even a champion if he gets too close. It will also push them back from your turret pretty quickly when they run out of minions to take hits. If you don't have that much gold, just get the scythe and you'll be able to keep farming while restoring health until you can get the tiamat. You may start to push to there turret if you have the upper hand so I suggest keeping a ward in the river still as you do this. You may get boots if you are constantly pushing there turret. I wouldn't suggest taking down the turret just yet. You don't want to be caught pushing too far without being prepared or even worse, have them retaliate immediately by pushing your lane hard. So just wait, get that last bit of gold to upgrade to Ravenous Hydra and then take your boots to the berserker stage. Now you can probably swing by the wraiths and/or wolves for some extra gold. You can even slay the ancient golem, even without the shoes. You won't even lose any health. At this point, you may feel free to take down the top turret, once you do this, you can return to the jungle and/or help out the other lanes. You should be pretty powerful in small group fights at this point, especially 1v1, as long as no one got too fed. You should always keep an eye out for your own lane, taking care to eliminate all threats that come to your turret. Eventually, after either killing champions easily or having to farm jungle and minions, you should be able to get bloodthirster. This will give you most the damage you'll need for the game. Coupled with the lifesteal you should be alright in most fights. You shouldn't need any wards at this point, just be careful, but it's never a bad idea to have a ward around. Everyone should have wards, aside from maybe the adc, but late game when people demand wards, they should probably just grab their own. Lot's of times I see teams getting beat back to there base to defend, and then someone will say, get baron warded. Which is fine, but it can be challenging to get out of the base without being ganked when there are no wards already, especially when the enemy isn't dead, just waiting for you somewhere. It's just better to play it safe when your team is going negative, rather then to send someone to ward a place where, if you tried to gank, would be destroyed anyway. Anyway, point being, wards are good for everyone to buy, especially before everyone starts to get ganked... It's best to try and keep your kills higher then your deaths, this should determine how you play the game, if you have a significant lead in kills, your team should be really well built, compared to the enemy. So if everyone is playing well, and you haven't been unable to farm, then you should be getting kills and assists and helping take down any champions who are still alone. At this rate, you'll just need to get phantom dancer, statikk shiv, and blade of the ruined king to finish the game out hard. It will be very hard for anyone to escape when you have an extremely high run speed, if anyone tries to counter by getting movement speed, they'll just be wasting gold that would otherwise be used to increase there damage. That's just the best case scenario. You'll be adding movement speed, attack speed, and critical strike chance with both the phantom dancer and statikk shiv. You'll notice your able to take down turrets and get away without a problem. If anyone comes alone to stop you, they won't be able to survive long. Be careful though, even though you can basically kill anyone, if they can stop you from attacking anything that grants you lifesteal, you'll die. We give up our armor so that we can move as fast as possible. In turn, we have the ability to take out AD opponents easy, even tanks, since your damage will no doubt feed you enough health to outlast them. Once they're dead just hit the passing minions and your lifesteal will do the rest. Which is why, even in the very end, why not just push our limits with the blade of the ruined king. Adding our final stats of even more attack speed, lifesteal and damage. The only trick will be not giving them time to focus fire on you in teamfights, but with the kills you guys should have, no one should be under built. If worse comes to worse, just take down the enemies turrets and inhibs all by yourself, it's worth a shot if you're really being outplayed. It's a shifty win, but if they can't stop you in time, then it's still a GG.

The Runes I have for armor and magic resistance are for playing a tank, but using them here helps out a lot when your trying to gain the upper hand against a tough opponent. Attack speed could not be any more useful for holding the lane once you get lifesteal. You can wear down your opponents health by attacking them and then switching to minions to restore your health. They won't be able to keep up and you'll be able to finish them off with ease. The quintessences are really up to you, I just use what I have, but they work for me. The lifesteal isn't much, but it's still lifesteal. Armor pen is always good and more attack speed brings it close to 19% to start, which adds up pretty quickly with your shroud of darkness.

Nocturne top is focused mostly on doing direct attack damage. Duskbringer will be used mostly to force a champion back and to get in some hits before taking them on directly. Shroud of darkness will be priority in basically every situation. The permanent attack speed increase with each level will become your strength. Try to avoid getting too aggressive too early, it's important to survive more than kill at this point, don't push the lane if you don't have too. Let them back you against the turret, this way you can save your ward for when you're pushing them. Your passive will allow you to heal yourself when hitting minions every 10 seconds, so you shouldn't need any health pots, especially since you'll be rushing the vampiric scythe. It'll be good to have unspeakable horror ready for when you are going in to a fight, this will buy you extra time or just cause the enemy to run away. Either way will allow for you to hit more minions and regain some health. Always be aware of your lifesteal, it will be your greatest strength. Using the method of chipping away with duskbringer before engaging battle could easily give you a kill. Save your Paranoia ultimate for when they have less then a quarter health left, it will ensure there defeat, even hit them with ignite at this point. Duskbringer should still be enough to finish off a fleeing champion or at least give you the speed bonus from the trail to allow you to catch them still. Even using ghost if it's that important that you kill them. A dead champion is a sad champion, especially one who won't get a kill in return. Don't forget to use shroud of darkness when your both starting an obviously battle that will surely end in death. They will most likely try and kill you by using some spell which you will block and then have even more attack speed for a moment, that's when unspeakable horror is best, they might try to run just then since there spell didn't land, but you're too fast and they stopped attacking you so your stealing there life and they go into a fear, you have that little bit of increased attack speed still and you make quick work of them. Then you turn to minions and get all your health back, it's pretty simple. Avoid using your ultimate on champions who are all full of health. It works best on ending a 1v1 or jumping into an already initiated fight where the enemy has there spells on cooldown and they're all losing some health and focusing someone else. That will be when you jump in and start eating people's faces, use unspeakable horror, and duskbringer to scare people away, shroud yourself just in case someone saved a spell for you. As long as they don't all focus you then you'll just cut right through them. There is one thing to beware of when doing this though. If the enemy is grouped too closely, and your allies are not right on top of them, then when you use paranoia, all the enemies will only be able to see you and they will only attack you. So try and attack when they are just a tad been strung out or if your allies are right on top of them aleady. Everything else should be a cakewalk.

Pros

• Lifesteal will sustain you
• Attack speed will allow for quick dispatches
• Turrets will be like hitting super minions
• You'll be fed from minions even without champion kills
• You'll be a freaking nightmare

Cons

• Even with armor, magic resistance or health, you'll be squishy
• You may not win if your team doesn't keep a positive score
• You'll have to be close to your enemies to keep your health up
• CC will end you

Am I really going top with Nocturne? Yes, but only because someone is going jungle who is more likely to be better at top, but's okay you don't care, you're Nocturne, it's whatev. You help them get blue and swim your way to the top turret. ****, Singed is waiting for you and he's ready to gas the place. Too bad he can't do much yet, farm minions. You push a little too far for comfort, luckily you bought that ward. You place it in the bushes by river and carry on. Oh my it's some enemy jungler, good thing you're naturally pretty fast, but it's Master Yi! Quick use ghost to swim to your turret. That was close, time to shop. Hmmm, singed is gonna be poisoning my *** off, I should buy some magic resist, this Negatron Cloak should do nicely. Back to top, Udyr shows up, you hit level 6, Singed tries to get away, but it's too late. Night falls, you pounce, he gets feared, he tries to run, but you're Nocturne, no one escapes Nocturne.

You kill minions pretty nicely, but you crave more. You complete your Ravenous Hydra and Berserker Greaves. Suddenly everything makes sense. You push top and don't want to risk going to far, so don't. You notice some giant wolves, nobody will really miss giant wolves, not at this point in the game, NOM NOM NOM. Feeling greedy? No one's around, sure I'll kill an ancient golem, why not? Oh no, your top turret is under attack! You swim through the forest and what singed wants to throw you! Good thing you bought that magic resistance. Bash him up and make him run, hopefully Udyr will turn up soon to help finish him off. Finish off some minions to get some health back. Repeat the fast and easy kill pattern. Rack up over one hundred minion kills super fast. Even if I don't get any champion kills, I've still got it made.

If you're doing really well, which let's assume you are, then you should have decent speed,damage,and lifesteal. Early to mid game, you will survive most 1v1 fights if not 1v2. As long as you can get in close to your enemies, you'll be able to do stay alive fairly well. Try not to get to cocky, once they realize they can't be near you, they'll kite you as hard as they can. Without much protection, you can be starved to death by range. Eventually you may have to stop trying to solo the whole team. It's important to get as many of those surprise kills in before late game. Once late game comes, if you're team isn't doing so hot, try focusing on pushing lanes fast and getting turrets. Nocturne will be able to move fast and hit fast, making easy work of turrets and inhibs. Also, if you're losing, you may want to risk backdooring, especially since if you have to fight one champion, you'll most likely win and reheal with lifesteal. You can destroy their entire base before they can if your team can hold them off.

Fighting is easy, you mostly just auto attack, but if you want to use mana, then yea, use duskbringer to hit those hard to reach targets. It makes a handy little escape tool, although stopping for a second to cast it makes it dangerous. I'd do it if it looks like they might catch up and I really need to get away, otherwise I'd like to think my desire for movement speed would be enough for me to get away, not to mention having ghost. Obviously duskbringer is best when initiating since it adds more damage and also when they start to run, since Nocturne moves faster in the trail. Shroud of darkness is maxed first for the attack speed, but don't forget it can stop an enemy spell, which if used right means certain doom for the enemy. I'd suggest using it when they are obviously about to engage you in battle or as the game suggests, once you use your ult to jump on them since they might freak out right then, but this isn't jungle Nocturne, this is top Nocturne. I would suggest using your ult when an enemy is below half health, this will basically seal their fate. This is also a good time to use unspeakable horror if you haven't already. This will by you that few seconds to lifesteal there health and gain a quick advantage for when his friend shows up in a few seconds. If it's someone squishy, you can usually take them out if your abilities are ready to go, even without them, your lifesteal should be more then enough to keep you up for the few seconds you need to take someone squishy down. They normally don't run since your health looks low, but as long as you are attacking, with your ravenous hydra hitting minions walking by or whatever, you'll just keep going and going. This is usually how it can go unless your team is not working out. You might get screwed, but that just means you need to rake in more gold with your infamous ravenous hydra in the jungle and any lane at all. Ignore calls for team fights if you notice a severe lack of kills to death ratio for your team, more than likely that means you can't take on the other team anyway, so just push lanes and avoid being ganked. You'll have to scrape up some gold fast and get some more of those items if you want to be of any help. In the end, it may come down to having enough attack speed to quickly take down turrets by yourself. This may buy you enough time to build up your last few items, or simply scramble the enemy team into running into you alone in the jungle. Most likely you'll just be running around with your team killing stragglers who can't stand up to your OP team.

Singed is the worst person I could imagine fighting as Nocturne. He is also the first one I went against when I tried this build out. I started out with a hunters machete and 5 health pots. I was originally supposed to be jungling but Udyr decided he wanted and I decided not to say a word. He had Revive and something equally awful as his spells. Granted I had ignite anyway because I loathe smite. Anyway, so even with what items I had, I went against Singed. I started out aggressive because I knew what was coming and I had to get in some farm before I had to deal with that, but here's the strategy. He gets that gas trail, don't worry, just hit him once when he comes towards you or runs by and then just back away. You'll want to get the Negatron Cloak thing for this battle because you will definitely be in that gas. I bought the vampiric scythe, and then went straight for the cloak. The most important thing was not letting him get any kills from me. So hitting him with duskbringer and using everything you can, you should actually be able to take him down in his own cloud. Especially if the jungle helps. I suggest getting him down a few times to really mess with his build and to make yours happen faster. Once you get that ravenous hydra, he should no longer be a problem. You can keep the MR cloak for a while just to be safe, sell it later if Singed is taken care of, or upgrade it to spirit visage if you want. It adds health and a nifty little thing to aid in your lifesteal. I'd reccomend skipping bloodthirster though and go for the the attack speed. If it gets too late in game and you aren't fast enough, then you might fall behind. The lack of damage should be alright since you have the increase to health and health regen. Also you'll steal get that aid to your lifesteal and keep the MR. As long as Singed doesn't get fed, he shouldn't become to strong, although he is still a pretty tough champion since he can farm minions easy as well.

Now I fought Rumble next and had to get the cloak again as well. It saved my life. I'm not familiar with Rumble, but I noticed that when I got him close to death and I seemed to have a lot of health still, mine would suddenly drop significantly and I almost died. Once I did, very unexpected when I thought he was screwed. I made sure to use Paranoia when he got close to death the next time and it did the job, my health did almost drop completely though. This battle involved a Blitzcrank as well and he ended up being easy just because of my attack speed. This battle went a lot better and I ended up selling the Magic Resistance Cloak and getting the bloodthirster instead.