Honestly speaking it seems that the NF.PeoplePickerAPI is not present in the Office 365. I checked that object and there is no such node.
Anyway, I have other solution for you. Tested and working. Use the following code:
NWF.FormFiller.Events.RegisterAfterReady(function () {
NWF$(document).ready(function() {
NWF$("#"+var_People1).change(function() {
NWF$("#"+var_People2).val("");
NWF$("#"+var_People2).closest("div.ip-container").find("div.ip-item").each(function() { NWF$(this).remove(); });
NWF$("#"+var_People2).val(NWF$(this).val());
NWF$(this).closest("div.ip-container").find("div.ip-item").each(function() { NWF$("#"+var_People2).closest("div").find("textarea").before(NWF$(this).clone(true,true)); });
});
});
});
Obviously the var_People1 and var_People2 are JavaScript variables set for you two fields:

Bon appetit! 
Regards,
Tomasz