Nightwing was a spur of the moment paint job a few days ago. While waiting for some washes to dry on another batch of figures I ended up alternating work on him. Although initially not very excited by the pose I'm really quite pleased with how he turned out. He took also took a minimal amount of time to do, clocking in at under 45 minutes start to finish including dry time.
After priming him grey I applied two thin coats of black to get nice even coverage on the suit and mask. I followed that with a wash of GW Asurmen Blue, and once dry applied a light dry brush coat on all the black of AP Uniform Grey. It has a slight touch of blue in it and brought out the models details perfectly. The hair was done the same way, followed with two ink washes of black.
On the blue detailing I painted a solid coat of P3 Platinum which I followed with two even coats of Tamiya Clear Blue. The face was done with a base coat of GW Flesh and then some highlight of Elf Flesh.
In terms of gameplay I think Nightwing is one of the best Batman-affiliated free agents for his points. If he is ideally positioned and undamaged he can attack twice in the same activation, using 3SC+1AC for Electric Storm, and the remaining 2AC to net another three attacks through combo with his electric baton. Handy and mechanic mean you're very likely landing two of those attacks.
The biggest challenge to laying down that kind of beating is his 6 willpower. If you've suffered anything more than 1 damage you'll be unable to do this, so if possible, picking up a Titan on the way to the fight is crucial.
Nightwing is also highly mobile with Batclaw and Acrobat. He can get where he needs to be faster than most free agents, climb scenery more easily, and with Sneak Attack can stop his target from defending in certain situations. He also has some ranged weaponry when necessary, although I'd suggest saving those as a last resort.
In my last game using Nightwing I was able to knock down AK Red Hood, forcing him to flee combat or take a KO in the next turn. Shortly after I was able to land several solid hits on Dark Knight Returns Batman and KO him. To add insult to injury, acrobat let me climb up to activate the Batsignal for another 4VP that same round. I know I won't always be that lucky, but the potential for damage output, combined with his mobility makes him a current favorite for now!