Who was the Nationalist leader of Ethiopia during decolonization?

The Nationalist leader of Ethiopia during decolonization was Emperor Haile Selassie.

What was the political party called

The political party associated with Emperor Haile Selassie during his reign was the Ethiopian People's Revolutionary Democratic Front (EPRDF).

Was Libya renamed after gaining independence?

Yes, Libya was renamed after gaining independence. It was originally known as the Kingdom of Libya when it gained independence from Italy in 1951. In 1969, following a coup d'état led by Muammar Gaddafi, the country was renamed the "Libyan Arab Republic." Then in 1977, Gaddafi proclaimed the country to be the "Great Socialist People's Libyan Arab Jamahiriya." Finally, in 2011 after the overthrow of Gaddafi's regime, Libya's official name was changed to the "Libya" that is used today.