No legitimate "God Mode" exists in Call of Duty: Black Ops on Wii. The game does not include developer cheats for invincibility in any mode.
04xxxxxx 4E800020 (branch always) *can* freeze health, but:
SB4E01 (Black Ops Wii). Example: 28200FA0 00008000 + 04Axxxxx 437F0000 (Health).Don't risk a console ban for a code that desyncs you. Play smart, use Flak Jacket, learn the maps.