I started by checking my own Global 1940 map analysis document…
…and the entry for Chile says “Chile, a country with close trading ties with Germany, initially chose to remain neutral (in contrast with many South American countries which, although technically neutral, tilted slightly towards the Allied side early in the war). Chile only started to distance itself from the Axis powers in 1943, when it broke diplomatic relations with them.”
According to this page…
https://en.wikipedia.org/wiki/Allies_of_World_War_II
the “Declaration by United Nations”, originally signed by 26 nations in January 1942, was signed by Chile in early 1945. Chile was also one of the original 51 signatories of the 1945 Charter of the United Nations, and Chile also apparently declared war on Japan in April 1945. This page…
https://en.wikipedia.org/wiki/Declarations_of_war_during_World_War_II
…similarly notes the same declaration of war against Japan and similarly mentions none against Germany.
All in all, it sounds as if Chile was one of the countries (there were several, notably in Latin America) which spent much of WWII playing their cards close to their vest, and which only committeed themselves to the Allied bandwagon once it was clear that a) the war was nearly over and b) the Allies were going to win. Based on the other entries in my map analysis document, it looks as if, basically, the Latin American countries whose real inclination was to be pro-Axis spent the war pretending they were neutral; the Latin American countries whose real inclination was to be neutral spent the war pretending they were pro-Allied; and the Latin American / Caribbean countries whose inclination was to be pro-Allied jumped onto the Allied bandwagon right after Pearl Harbor. The reason for all of these positions (nuanced or overt) isn’t hard to guess: they were all in the western hemisphere, i.e. in the backyard of the United States, so they had to be careful about the public stance they took, even in those countries with right-wing governements and/or significantly large numbers of residents of German ancestry.
