I have a new 3ds running Luma, and am currently working on getting a gba emu for my R4 card (wood firm ware). While searching through that I ran across a very simple to use .nds that works as an nes emu. It's quite ingenious actually, the Emu runs as just like any other .nds game, but it enables you to run all your .nes games. Now if only they could make something like for GBA!!! lol
https://sourceforge.net/projects/nesds/
https://sourceforge.net/projects/nesds/
