If Volatile Fault's ability resolves, the target nonbasic land's controller gets to search for a basic land card even if the land wasn't destroyed by Volatile Fault's ability. This may happen because the land has indestructible. In this case, you'll still create a Treasure token.

If the target of Volatile Fault's last ability is illegal as the ability tries to resolve, it won't resolve and none of its effects will happen. You won't create a Treasure token.