Hmmm difficult one that TBH. The Chord which most closy resembles the NAC A5 sonically is Chord Signature which is hugely expensive, some say better but theres something about the NAC A5 (not just the price) that means it just works with Naim systems.
Seeing as you are not using Naim Amplification i would suggest a listen to QED XT Evolution Speaker Cable which is quite nice
Atlas hyper 2.0. Used this pre my Naim system with an Arcam set-up and it sounded much better than the QED silver anniversay XT and a little better than the Van Damme LCOFC 6mm, that I had used previously.
In terms of pure value for money check out the Van Damme, but for sound the Atlas was just a little better and last time I looked it was the same price as the NACA5