Nandbin Melonds !free! <4K>

The nand.bin file is the key that unlocks full DSi emulation in melonDS. While obtaining it requires a legitimate dump from your own hardware, the reward is a highly accurate and powerful way to play DSiWare and DSi-enhanced titles on a wide range of platforms, from Windows PCs to the Nintendo Switch.

Just having the NAND file isn't enough; you need to get your legally-owned DSiWare games ( .nds files) onto it. The standalone version of melonDS has a built-in tool to do exactly that. nandbin melonds