Do you already have the or BootMii installed?
If you need to download a NAND backup file, you can try searching for it on reputable websites that offer Wii console resources and tools. Some popular sources include: Wii Nand Backup Files Download
When you perform a backup, two specific files are created on the root of your SD card: : The actual image of your internal memory. : Your console’s unique encryption keys. Why they are unique : Every Wii has its own set of keys; you generally use another person's on your console without advanced modification tools like to resign the data for your specific hardware. Creating Your Own Backup Do you already have the or BootMii installed