There is no cheat code named "Easy Expert" in Guitar Hero III: Legends of Rock. However, the game includes built-in modifiers that make Expert difficulty more accessible:
Most are unlocked by default or via Career progression. "No Fail" may require completing a venue or entering a code (varies by platform).
Tip: Consistent practice on Practice Mode + Hyperspeed 3–5 + No Fail is the real "easy expert" path.