With this USB-C cable, any USB-C power supply that provides at least 30W of power at 12V can power your Wii.
Compared to the original Wii power supply, modern USB-C power supplies are usually much smaller, lighter and more convenient in terms of wiring options, which make them a better choice particularly when traveling.
In order to power your Wii with USB-C, there are two different approaches: either you replace the power connector in your Wii to USB-C, or you use an adapter cable like this one.
The Wii power connector is much more robust than USB-C receptacles, so this adapter cable provides the convenience of USB-C power without sacrificing your console's sturdiness.
You can buy a matching power supply that I've confirmed to work with a Wii console (when running Gamecube games) reliably here:
Total length (plug to plug): 202 cm (±2 cm production variation range).
Weight: 54 g.
Weight of matching USB-C power supply (sold separately): 40 g.
Weight savings compared to an official Wii power supply (EU 230V version): 436-(54+40) = 342 g.
