i would use my powers to make some of the Years of Rice and Salt stuff happen. ideally do the thing where the black plague kills 99.9% of europe and just see what happens. but since the book is written by a Materialist, he recognizes that other cultures from North Africa and Asia will just move in and do Imperialism eventually just in a delayed fashion. so maybe the delay will give an edge to the colonized peoples?
still might get that massive central Asian world war from the book but it's basically the biggest and only global war and long before nukes. but hey maybe you also get Communist Haudenosaunee superpower that helps everyone rebuild and the world transitions to socialism during the reconstruction