I don't know of *any* Irish songs about the Great Hunger; "Over Here" or "The Praties They Are Small" is in fact a song written by Irish emigrants in America.

It's a bit like the Holocaust; survivors' guilt and pain means they don't want to sing about how they survived and how the people they loved died.

You might be interested in reading Thomas Kenneally's The Great Shame, which is about the Fenians, the transportations to Australia, the Famine and that whole period; he has a good take on the guilt, and how the Famine changed Irish society from one based on bonding and generosity to one where suspicion and greed were necessary to "get ahead".