You can win with on-hit but I don't think it's optimal. Bruiser works better vs tanky teams. If you go for mostly attack speed items, it's hard to get enough attacks off to make them worth it 'cause you'll be quite squishy.

Duskblade of Draktharr gives you ability haste, which lets you cast your ultimate more often, and invisibility after you 1-shot someone. It also deals basically the same damage as Eclipse until later in the game, when Eclipse's mythic passive is stacked up. I'd recommend Duskblade as it'll give you more opportunities to get kills and you'll be safe from being focused after killing someone, because you'll be invisible long enough to reposition.

Generally when the enemy team isn't squishy / vulnerable enough to use a full damage build. If you're against a lot of tanks/bruisers, peeling supports like Lulu, and the enemy team is going to be grouped a lot of the time, it can be basically impossible to reliably 1-shot someone.

The Bruiser build still lets you kill people, but you'll do it over time and you'll be a lot tankier for team fights. It's not as strong at carrying, since getting picks solo is more difficult (the enemy has more time to escape or get help), but it guarantees you won't be useless in team fights.

For example, I used the bruiser build against a team with Renekton, Rek'Sai, Sylas, Miss Fortune and Maokai. I could probably kill any of those champions with the Assassin build if they were alone, but when grouped, my only viable target would be MF (and she built Zhonya's Hourglass that game). Instead, I was able to fight anyone on their team, even in team fights, since I couldn't be bursted through Sterak's Gage and had enough DPS from Lethal Tempo to kill their tankier guys.

Wow, I didn't even realize they changed the name. Thanks for the tip, I'll update the guide now.

Lethality items look pretty good but it's hard to say for certain what options there'll be. Nocturne has historically had pretty radically different builds based on which items are strong. I'm hoping we'll end up with more build flexibility than there was for Noc this past season, but there's a lot of uncertainty with PBE testing so I'll reserve judgment for when the preseason patch actually goes live.

I usually post a comment for any major updates.

I tend to favor the assassin build since I have a lot more experience with lethality items on Nocturne. I tend to perform well with that build unless the enemy team is really resilient against burst damage.

I would say give both builds a try for a handful of games and see how they feel, but there's nothing wrong with sticking with the bruiser build if you have more success with it. It tends to work better against comps that counter Nocturne so it should work okay in any game. Lethality is easier to counter but stronger in the right circumstances.

If you were able to carry a 30+ minute game without dying a lot it means you have decent enough fundamentals to figure out how to be effective without jumping into 5 people and dying or something, so if you keep playing him I'm sure you'll get the hang of the champion. I think Nocturne is really strong below Diamond so he's worth the time investment. :)