The Biorb brand lights won't work for coral. Unfortunately, the Biorb is not so suitable for a SW nano due to its shape (and thus lack of gas exchange relative to a rectangular tank of the same volume). I'm not too well-versed on sumps, at least until I get my 50 gallon

, but I can't imagine how you would work out a sump with the Biorb.
If you really want to try this project, perhaps you could use a powerhead for circulation, and try using the Coralife 2x9W PC light. The mounting legs don't work w/ the 18W model, so I suspended mine above my 5.5 gallon tank. However, I warn you that 18W would be an absolute bare minimum, IMO, for even low light coral (as I believe that the Biorb is 8 gallons?). You could try a larger PC strip, but I think it would just hang over the sides of the Biorb.
My advice, if you really want a nano, is to go with a 5.5 gallon rectangular tank, or larger. It will save you many headaches, I am sure, and the tank would only cost you about $10. Given that you'll need to replace all the proprietary equipment anyway (corals don't like the bubbles that the Biorb pump-driven filter will generate), it won't cost much more at all.
Good luck!
