A lot of these nations are identifiable. It's clear he is starting out from Adulis and conquering south from there.Having after this with a strong hand compelled the nations bordering on my kingdom to live in peace, I made war upon the following nations, and by force of arms reduced them to subjection. I warred first with the nation of Gazê, then with Agamê and Sigyê, and having conquered them I exacted the half of all that they possessed. I next reduced Aua and Tiamô, called Tziamô, and the Gambêla, and the tribes near them, and Zingabênê and Angabe and Tiama and Athagaûs and Kalaa, and the Semênoi ---- a people who lived beyond the Nile on mountains difficult of access and covered with snow, where the year is all winter with hailstorms, frosts and snows into which a man sinks knee-deep. I passed the river to attack these nations, and reduced them. I next subdued Lazine and Zaa and Gabala, tribes which inhabit mountains with steep declivities abounding with hot springs, the Atalmô and Bega, and all the tribes in the same quarter along with them. I proceeded next against the Tangaitae, who adjoin the borders of Egypt; and having reduced them I made a footpath giving access by land into Egypt from that part of my dominions. Next I reduced Annine and Metine----tribes inhabiting precipitous mountains. My arms were next directed against the Sesea nation. These had retired to a high mountain difficult of access; but I blockaded the mountain on every side, and compelled them to come down and surrender. I then selected for myself the best of their young men and their women, with their sons and daughters and all besides that they possessed. The tribes of Rhausi I next brought to submission: a barbarous race spread over wide waterless plains in the interior of the frankincense country. Advancing thence towards the sea, I encountered the Solate, whom I subdued, and left with instructions to guard the coast. All these nations, protected though they were by mountains all but impregnable, I conquered, after engagements in which I was myself present. Upon their submission I restored their territories to them, subject to the payment of tribute. Many other tribes besides these submitted of their own accord, and became likewise tributary. And I sent a fleet and land forces against the Arabitae and Cinaedocolpitae who dwelt on the other side of the Red Sea, and having reduced the sovereigns of both, I imposed on them a land tribute and charged them to make travelling safe both by sea and by land. I thus subdued the whole coast from Leucê Cômê to the country of the Sabaeans. I first and alone of the kings of my race made these conquests. For this success I now offer my thanks to my mighty God, Arês, who begat me, and by whose aid I reduced all the nations bordering on my own country, on the East to the country of frankincense, and on the West to Ethiopia and Sasu. Of these expeditions, some were conducted by myself in person, and ended in victory, and the others I entrusted to my officers. Having thus brought all the world under my authority to peace, I came down to Aduli and offered sacrifice to Zeus, and to Ares and to Poseidon, whom I entreated to befriend all who go down to the sea in ships. Here also I reunited all my forces, and setting down this Chair in this place, I consecrated it to Ares in the twenty-seventh year of my reign.
1) The "Gazê": Here he's conquering Akkele Guzay, the Gazê are also known as the Agazyan or the Ge'ez or the Xabasha, Who were the Aksumites if they weren't Xabasha? Good question!
2) The "Agamê": The inhabitants of Agame, who's capital was at Matara. Ethiopians call them "Belew Kelew".
3) The "Sigyê": Considering where he goes next, this is probably a nation who originally lived around Entitcho. Debre Damo is located in this area
4) The "Aua": This is a nation that lived around Adwa. Adwa means "Ad Aua" the city of the Aua.
5) The "Tziamô": This probably referes to Tembien, south of Adwa
6) The "Gambêla": This refers to the Jambela valley of Enderta, probably named after the people who lived there.
7) The "Zingabênê": Probably the original inhabitants of Mek'ele
8) The "Angabe": Other inscriptions of Ezana's campaigns put Angabe in Agaw country as well, probably the the original inhabitants of Saloa
9) The "Tiama": Probably the original inhabitants of Abergele, along the Takezze
10) The "Athagaûs": Probably a branch of the Agaw native to Woggerat
11) The "Kalaa": Kalawe is on the other side of the Takezze
12) The "Semênoi": Finally a name that survived, the Semien Mountains, these are the Qemant (or Falashas) he's attacking now, probably what is now Tselemti
13) The "Lazine": Lazen is where King Kaleb is from. Probably the original inhabitants of Waldebba
14) The "Zaa": Probably the original inhabitants of Woggera
15) The "Gabala": Probably the original inhabitants of Dembeya, challenging territory indeed, centered around Gonder
16) The "Atalmô": Probably the original inhabitants of Fogera, along the eastern shore of Lake Tana.
17) The "Bega": He's actually referring to the Bega of Begmeder, not the Beja of Sudan
18) The "Tangaitae": He is done with his southern conquests and this is clearly a new campaign, this time in Eritrea. These are probably the original inhabitants of what is now called the Sahel region. He says this gives him a border with Egypt, which must mean this conquest is occurring in the time of Ptolemaic Egypt's rule over Suakin (they called it Limen Evangelis), so the 1st century or so!
19) The "Annine": Probably the original inhabitants of Senhit.
20) The "Metine": Mentioned in other inscriptions, the original inhabitants of Hamasien.
21) The "Sesea": Probably Debarwa, with it's forbidding mountains. He doesn't go any further west, turning east again.
22) The "Rhausi": The original inhabitants of the Danakil Depression, probably long since absorbed by the Afars
23) The "Solate": The original inhabitants of the Buri Peninsula and northern Danakil coast
My interpretation is he never went south of Lake Tana, never went west of Eritrea, and never went east of Hawakil Bay in the Afar country.
No Ethiopian conquerer ventured into Somali lands until Amde Seyon.