BD+C is fine, as it has a landscape component with the WE credits and many of the concepts of ND are already there. If you want to get ahead and go into an LA firm, familiarize yourself with the Sustainable Sites Initiative, which is like LEED for site work. There is no exam, and the download is free.
I have BD+C and don’t feel the need to go back for ND just yet. I don’t think it is refined enough in its current form. For the type of work I do, ND is not really applicable, but BD+C is.