The two most common System/Turret pairings I've seen for Nym are
- Advanced Sensors / Twin Laser Turret (for guaranteed actions and more damage area)
- Accuracy Corrector / Autoblaster Turret (for 2 unblockable damage)
After seeing someone cross-mix AS with ABT against me and easily reducing me to one shot on Nym every other turn with my two remaining arc-bound ships, I'm now convinced that's the most potent combo for the points. And I've thought hard about why that is.
3 points for AS lets Nym move like a pre-nerf TIE Phantom. One more point lets him do it at PS 10 -- better than any Phantom can do it. Also after anyone who isn't another PS-boosted Ace. I even wrote a simulation to show me exactly how many positions Nym can be in where he has a move he can dial in which, in combination with an optional barrel roll either before or after moving, guarantees a dodge vs. all possible opponent maneuvers. Here's what the results look like for an X-Wing:

An X-Wing in one of those positions and orientations pre-maneuver might get a shot in, if Nym guesses wrong. Anywhere in the black, it won't. (Caveat: This is not an exhaustive sampling of positions and angles, and I don't check for all possible corner cases, but it's accurate enough to give a general overview.)
Of course, the drawback of arc-dodging is that you often deny yourself a shot as well. Enter the Autoblaster Turret, which corrects that for a measly 2 additional squad points -- in a situation where its maximum range of 1 usually doesn't matter!
So, in summary:
- Nym isn't strong because he has infinite bomb ammo. Nym is strong because he dodges arcs better than Phantoms did when Phantoms were so good at arc-dodging that they broke the game. The bombs are just a bonus.
- Autoblaster Turret isn't strong on Nym because it causes unblockable damage. It's strong on Nym because it lets him shoot reliably in all directions for only 2 points.