I assume I don’t need to provide sources for operation paperclip as it is well known.

• Kissinger approved Argentinian ‘dirty war’ - Declassified US files expose 1970s backing for junta | The Guardian archive
• Peru’s coup-plotting congress has 6% approval, 91% disapproval (but full US backing) | Geopolitical Economy Report
• US President Bush praised dictator Fujimori as ‘Peru’s hope for the future | Geopolitical Economy Report
• Augusto Pinochet - U.S. backing of the coup | Wikipedia

As for the Nazi part: these counties were popular travel destinations for Nazis trying to escape prosecution, with Argentina being especially known for this, who then helped exterminate political opponents in concentration camps. This is more relevant to the earlier Peru’s coup however.