I'd recommend clear-paths, but that's pretty dependent on which champion you choose. I almost always start bot-side so the adc and support can help with the first camp, so a typical blue side clear (for Nocturne) is: 1. Krugs (smite) --> 2. Red Buff --> Scuttle Crab --> Wraiths then/or recall, upgrade jungle item (rangers, since you'll be farming) + health pots + ward; then do the blue buff side.
The cool thing about Nocturne is that he's really versatile- Devourer is probably the strongest for him right now, but Warrior is perfectly viable and gives him early dueling power, and Cinderhulk is available if you fall behind and need to be the tank. Unfortunately, he's pretty team dependent. If you dive in, you have to hope your team is in position and willing to go in with you, or else you will be left to die a lot. Sejuani and Gragas are probably safer picks, but out of these i've only played Nocturne, so that's all i can advise you on :P
If you are worried about an early invade, start at your Red Buff first, then go to Wolves then Blue. For Nocturne specifically, be warned that building glass cannon on him is something of a noob trap. Besides the jungle item (if you're going devourer, you want to complete that ASAP), you'll only need, at most, one more damage item (Youmuus, Hydra, BoRK, Maw of Malmortius [Nocturne is one of the few champions this item is strong for] etc.), and the rest should be tank items (Randuins, Spirit Visage, Thornmail, Banshee's Veil, etc.). Often, you'll the primary or secondary initiator, so you need the survivability. Only focus building damage items if you are super-duper fed early in the game.
I recommend picking up the clairvoyance trinket later in the game; it will save you frustration when you turn on your ult, and can't use it because they ducked into the fog of war. Admittedly, this will be dependent on your team picking up the warding slack.