well, I don't know about 3DSNUS, but at that ISO site, in the thread with all the 3DS updates, is the Spider Browser for the OLD 3DS, and I think whichever one is exploitable for the NEW 3DS.
I have an o3DS, and what I did was download the Spider browser from that ISO site, and using Big Blue Menu, first uninstall the old browser, and then install the Spider cia.