Which people? The Europeans were occupied or liberated under effectively caretaker governments. Americans didn't need pacification.
> the agreements that came out of those trials
The trials inspired some agreements. It didn't create any, other than the precedent of holding leaders accountable for crimes against humanity.
They were occupied but they weren't entirely busy: while "low" people were happy to kill ex-Nazi collaborators themselves, it's the post-war governments (all of them, USA's included) who needed, with those trials, to manifest a re-establishment of the rule of law once again. 80 years later we can see it's been a hypocrite farce in every part of it, but it saved lives, those that were worth of living, although spared Nazis, fascists and sometimes communists too.
Do you have a source for this having been the motivation?
I’m admittedly most familiar with the French and American perspectives. Those weren’t concerned with pacification but creating an international sense of the rule of law and legal basis for the occupation and restructuring of those societies.