Instead of jumping straight into a game, you can boot into the classic Wii dashboard.
If you own a Wii or Wii U (vWii), this is the most reliable way to get a unique NAND. wii nand download dolphin high quality
A "high-quality" NAND typically refers to a full backup of a physical Wii's internal memory. This file contains the unique cryptographic keys specific to your console. Instead of jumping straight into a game, you