I've been told that Nikon's ViewNX2 can process RAW. In any case, I convert them into TIFF and processed in LR.
well Adobe just relaease a Nikon D600 Raw support (support for Nikon D600 is preliminary and there is a minor risk that the appearance of your images may change when the final support for Nikon D600 is available in an upcoming release)
Read more on NikonRumors.com: Adobe Lightroom 4.2, Camera Raw 7.2 released with support for the latest Nikon products | Nikon Rumors