This guy can, once per game, go anywhere, take all the actions, discard all the stress and place 1 ion token on an enemy. I had planned on showing a vassal map of the potential locations, but honestly, there are so many permutations of maneuvers and repositioning actions that it turns the map into a mosiac of overlapping Nien tiles facing in every direction. It's an expensive trick, but how much would you pay for the ability described in the first sentence? The number of potential victims goes up if you are the first player, so who cares about a bid?
Some people are on to Nien being good with Pattern Analyzer (PA). He gets to do a red maneuver, take the PA action (which does not take the place of or remove the Perform Action step), then discard stress, then take another action.
Adding Black One to this combo greatly expands Nien's options. The downside of course, is the Disarm or Ion token. If he does a red move, he can PA action, then ditch stress, then perform action for the slam, into another red move, which grants another PA action.
Static Discharge Vanes means that the enemy takes the Ion instead of Nien. Normally the downside of Static Discharge Vanes is taking a stress. But, Nien doesn't keep that stress.
Obstacles might get in the way of many of these possible options, but R5-X3 astromech allows Nien to ignore those rules, too.
It's like a tankier Guri that can go to even more places, get even more actions, and give an enemy an Ion token, too.
In my 10 or so games with it, I have always found a way to trigger it and it has always been game-changing.
This is dialed all the way up (add outmaneuver if you just can't stop yourself), but it can be paired back a bit by removing the mech.
Enjoy, internet!