During the period of foreign capital influx, Chile and the British established a relatively close cooperation and gained substantial funds through saltpeter mining.
With the British as its backing, Chile naturally didn't worry about the issues between it and Argentina. But the Argentinians weren't in such a good mood.
Looking closely at Spain's colonial scope in South America, Chile had already aligned with the British, making a fortune through saltpeter mining.
Bolivia and Peru, to the north of Chile, have also formed an alliance, with both countries united, their combined strength not much different from Chile's.
Conversely, Argentina, having tasted success in the Paraguayan War, doesn't have a reliable ally at this moment, and its development speed is nowhere near Chile, which has access to saltpeter mines.
In addition, Argentina has an even stronger neighbor to the north, Brazil, which adds pressure to the Argentine government.
