45 minute layover in NRT?
 

So I'm thinking about flying AKL --> SFO (via. NRT) on the following flights:

NZ99 AKL-NRT arrives 16:40
NH8 NRT-SFO departs 17:25

Will 45 minutes be long enough? I guess it's worth mentioning I will be in business class, so hopefully de-planing won't take too too long.

This is not a legal connection -- since NZ is in T2, you'll have to transfer to T1, and there's a 90 minute MCT. That's not to say you couldn't make it if you were lucky, but I would not recommend it, and especially not if the next flight is the next day.