Platensia - Genoese (later Piedmontese and Italian) control over the Plata estuary.
At first a cession of the border area between Brazil and Uruguay (Colonia) as a neutral buffer about 1660, later a slow inglobation of Uruguay first, and Argentina later, except the southern tip, Magellania, ending up as a frosty British colony. The Piedmontese help Rio Grande do Sul and S.ta Catarina to get free from Brazil, the two states are later annexed into the United States of Greater Paraguay giving them an Atlantic coast.
The Italians manage to maintain control vover the colony, in always weker forms, up to the rise of Fascism when a civil war breaks out and anti-fascist independentists gain the upper hand. They'll enter the war alongside Brazil in 1942 and will be among the Allied armies in Italy, freeing Rome as Clark mops up half a German army in Latium, as he should.
Nuclear power from 1957, never got thermo, nver enteerd NATO despite intense US pressure, remained neutral in the Cold War deploring both Soviet oppression and US-inspired state terror in the rest of Latin America (ushering in the horrible war of dissolution of Greater Paraguay, a south American Yugoslavia on steroids). In space with men from 1977 to 1984 with a short-lived national program, quashed as too expensive. Suffered heavy crisis from the eighties. Rebelled against IMF policy in the 2000s, suffering isolation, avoids the worst of the financial bubble by cutting links to most world finance and eciting the WTO. Very strong cultural ties to Italy, but when a B-like tycoon tries to get power in the late Nineties, the army stages the first coup since 1920 to oust him and quietly seize and nationalize all his assets. All in all a Christian social democrat, isolationist middle power with prosperous agriculture, reasonable industry and good public and private services.