After several years with various Nickel Boron-plated AR-15 components, I am of the opinion that they should still be lubricated just like any other bolt carrier group. It is important to note that I held this opinion even when I had relatively little experience with nickel boron.
Nickel boron is a coating used by FailZero on bolt carrier groups and is purported to reduce lubrication requirements - eliminate them, actually, but I'll stop lubricating my weapons when the owners of FailZero plate the internal components of their cars' engines with nickel boron and stop using oil in them (I do realize that there are other considerations with engine oil- just go with me on this). Now, don't get me wrong - it definitely does have a "slick" feel, and the FCG is devoid of any grittiness whatsoever. I would just continue to lubricate any critical part that was plated with nickel boron, such as a bolt or bolt carrier.
The comparison shown herein is not meant to be scientific in nature, but does accurately depict my experiences with Nickel Boron BCGs.