For SR5 is there a sourcebook which talks about what Countries dislike other countries and which Corps are rivals?

All the Corps are Rivals, in one form or another.

You can also generally assume the CAS and Aztlan don't like each other while the NAN nations, especially the Sioux Nation, don't particularly like UCAS. Nobody really like the Tir but can't really do much about them and Cal-free hates everyone but is so powerless no one cares. Oh and Quebec is just carrying on being Quebec.