Following the battle of Adowa the Ethiopian Emperor Menelik follows up with the invasion ad conquest of Eritrea. IOTL there were already attrocity stories circulating after the battle that Italian soldiers were castrated, although this seems to be a myth the ethiopians did horribly mutilate the
Italians native troops. Eritrea was ripe for the taking, there is a degree of conjecture about why it wasn;t particualrly as the ethiopian army had secured so much modern military equipment and amunition following the battle.
So Eritrea is captured, a black african leader has not only fought off invasion but followed it up with thte invasion and conquest of a bordering colony. Attrocity stories are already circulating and can only increase following the capture of a civillian populace. The Italians are humiliated. African nationalists have a very clear example of a european country being crushed and a colony "liberated". Would the conquest of a relatively small colony have a much bigger impact than the rebuff of an invasion? Would the neighbouring british presence just see it as the incompetance of the Italians and happily trade with Ethiopia or would the invasion of Eritrea force European intervention due to concerns over loss of prestige?