I'm really sorry. This jungle Nasus guide hurts.
You say "because you may consider this a 'Jungle' build does not mean that you have to begin in the jungle." and then your reasoning for smite is that you are jungling. This is a flaw within it'self. Tiamat is not a good item in general and your starting items are not going to give you much sustain in lane. Your starting skill choice is bad for a jungle guide. Especially if you start at blue.
I'm sorry but, as a pre-patch jungle Nasus player, this hurts me deeply.

The wriggle is just kind of a helpful mid game item while allowing you to build more gold for farming throughout the game. Like I said, if it don't suit your playstyle, then of course don't buy anything that another item would get a better use.
The biggest pro of why I chose to put wriggles in the guide is because of the possiblity of making Madrid's Bloodrazor if needed in the game. You may know before the match even begins if the enemy champions will have quiet a bit of health, but even if you don't expect it, few people getting HP can easily turn your normal lantern build into Bloodrazor instead.

I don't honestly have the best expressed guide when it comes to items, I honestly never build the same exact sequence, just because I feel the need for change depending on my counter to enemies but also the speed of how much gold I am farming and the ease of it.

I think I understand what you mean about the messing around in jungle though. Nasus is fairly simple to stay in lane with his passive life steal. I wish I had more games to attempt solo lanes. I find the hardest part of the game for any similar DPS build Nasus is just the beginning of the game. It can go either way depending on the enemy / teammate champions. If I got a burst dps helping harass, it tends to lead to a easy lane.
However, if the enemy champs outburst me / teammate, I find myself going back too much, not being able to reach the full potential of life steal which downslides into lower levels and slow gold buildment.

Thanks for the replies! =)

What's the point of a late wriggles? It's meant to speed up jungling, sustain, and help kill dragon lv 7. And this is a build that starts in lane and then goes to jungle? Just get a solo top and stay in lane all day (only possibly if you don't push with spirit fire and don't get ganked badly). This is far more effective then going in the jungle to mess around.