This probably isn't the place to talk about it (SPOILERS AHOY), but whatever, I'm cool with it.
Nanomanufacture ammo (coined "nanomachic" on whatever you stick it on) makes it so that your weapon doesn't require ammo. Since we're talking about a rocket launcher, which only takes one ammo at full capacity, it's not going to do anything different. Next time try it on the BFG.
I believe these kinds of thread should be lumped into a spoiler thread though, so it's not too cluttering.