Nien has an amazing ability. He's able to shed unlimited amount of stress tokens provided he meets the parameters. The go to upgrades are stress-inducing ones such as Push The Limit, Rage and even R3-A2 to share the stress to the target.
However, there is a lot of sneaky tricks to go with it, and the first one if Pattern Analyzer. This essentially allows Nien to move, perform and action, trigger Push the Limit allowing him to boost into range of an enemy ship at range 1, and then discard the stress token he's just received.
When it comes to the combat phase, if you have equipped R3-A2 and you're in range 1 of the enemy then whilst they will gain a stress token, you'll immediately discard your own.
Of course going off manoeuvres alone, the T-70 has access to 3 of them that will add a stress token to the ship. With Pattern Analyzer this is giving Nien a chance to boost into range 1 to shed the stress and then Push The Limit for another action for 2 stress tokens that vanish.
Vectored Thrusters is also a handy modification for re-positioning, however it does compete with Autothrusters for the same amount of points and slot.
Lastly, it is worth pointing out that frustrating cards that are stress-inducing to combat against such as Rebel Captive, Mara Jade, R3-A2 and Asajj Ventress will no effect Nien Numb if the parameters are met.