Mr Berisha, whose unfortunately named Democratic Party stole last year's elections, has promised to resign if the opposition Socialist Party, which was led from prison by Mr Nano, wins the new polls called for June. Should a free and fair election come to pass in Albania, where every 10-year- old seems to have a Kalashnikov, the smart money is on Mr Nano's party.
Mr Nano was released last week when the prison guards fled from his jail in Tirana, and has been enjoying the limelight since his sudden pardon by Mr Berisha.
The Independent was to have interviewed Mr Nano, but was stood up twice, first for a meeting with an EU delegation, and then for tea with the US ambassador.
Mr Nano has spent the week getting to know the envoys, most of whom arrived in Tirana after his trial in 1993. He has spoken briefly of his time in prison. "I have come out of hell," he told colleagues.
Despite his deference to the caretaker government led by Bashkim Fino, the Socialist Prime Minister, Mr Nano is undoubtedly the leader of the Socialist grouping. He was the fifth candidate proposed by the Socialists; the first four were rejected by President Berisha. But, as a free man, Mr Nano may face challenges.
"Now we have already started to criticise him. When he was in prison, he was perfect," Jonuz Begaj said with a laugh. Mr Begaj is a foreign affairs adviser to the Socialist Party but not, he emphasises, a member.
The Socialist Party headquarters in Tirana, a dusty building, is jammed with supplicants and supporters, most of them men; women appear to play virtually no role in Albanian politics, although a group mobbed Mr Nano this week, some shedding tears of delight.
But Mr Nano also travels with bodyguards who look very like the thugs protecting Mr Berisha. Some in Tirana fear the Socialists will arm their supporters, as the Democrats did.
Mr Begaj acknowledges the risk that the Socialists may abuse their electoral victory by crushing all dissent. But he believes Mr Nano, a liberal economist who refused to participate in his own show trial, will clamp down on such behaviour.
President Berisha has tried to portray the mutiny in the south as "Red Terror" sponsored by the Socialists, the heirs to Enver Hoxha's Communist Party. In fact, the Democratic Party and Mr Berisha are just as much the children of Hoxha as the Socialists. Nor are the rivals very far apart on party programmes. The two might claim there is an ideological gap but they have similar views, on land ownership, for example. Neither plans to compensate those whose property was seized by the Hoxha regime.
"Albanian Socialists are not socialists, in the same way that Albanian Democrats were not democrats," one independent observer commented.
It is hard to imagine Albania staging free and fair elections in June, analysts say, because of the amount of arms floating around and because Mr Berisha still wields a certain amount of power, despite losing control of state television and the secret police. However, the Socialists stand a good chance of winning.
The situation has been horribly confused by the uprising sparked by the collapse of several pyramid investment schemes. "Albanians know exactly what they don't want - Berisha - but they don't know exactly what they do want," said the independent observer.
The protest movement in the south has no political face yet, but the various "Salvation Committees" formed in towns across southern Albania have united over the demand that Mr Berisha resign at once.
The Socialist leader holds the ace. "Nano has one advantage," said the observer. "He has not had the chance to make mistakes. He had nothing to do with the pyramid schemes."