Why bring up the US government as a whole? History repeatedly shows that "US" intervention in South America need not involve the entire governmental edifice; in fact, the most famous and effective examples involve only three-letter agencies (eg, the CIA) and their financial hegemonic counterparts (eg, the IMF).

If ideological differences threaten international resource extraction -- and Boric's stance against Kast's plan of "empowering the security forces to more forcefully crack down on Indigenous challenges to land rights in the south of the country" certainly suggests such a threat to me -- then Something Will Happen, mark my words.

Everyone thinks they only care about their interests.

It's just that as they see it, it's not in their interest to do such things as admit they were ever wrong, and rarely in their interest to risk losing nebulous prestige from abandoning costly but disastrous policies, etc.