Thanks for the analysis.

The identification of Nod is technically undermined—we can't be certain of it. More to say about that after Eden.

The identification of Eden is most likely in Kuwait or Iran. Satellite photos and geological studies have found evidences of two other dried up rivers in the region, along with evidences of ancient grasslands, lakes, and forests. Kuwait, at the mouth of the Kuwait River, is rife with pebbles, which is a clue that river used to be there. Research reveals that a river used to flow across the Arabian peninsula, possibly what the Bible calls the Pishon. The gold, bdellium, and onyx that the Bible mentions are in the general region of Mahd edh-Dhahab in Saudi Arabia.

Nod is defined in Gn. 4.16 (correcting your reference of 3.16) as "east of Eden," as you say. By the way, the Mesopotamian flood hero, Utnapishtim, (in the Gilgamesh Epic) is similarly located "faraway, at the mouth of the rivers," east of the head of the Persian Gulf. If our identifications of Eden are correct, Nod is in present-day Iran.

Genesis 2

10 A river watering the garden flowed from Eden; from there it was separated into four headwaters. 11 The name of the first is the Pishon; it winds through the entire land of Havilah, where there is gold. 12 (The gold of that land is good; aromatic resin[d] and onyx are also there.) 13 The name of the second river is the Gihon; it winds through the entire land of Cush.[e] 14 The name of the third river is the Tigris; it runs along the east side of Ashur. And the fourth river is the Euphrates.

This verse places the Garden of Eden in modern day Mesopotamia, between Basrah and Baghdad
Genesis 3

13 Cain said to the Lord, “My punishment is more than I can bear. 14 Today you are driving me from the land, and I will be hidden from your presence; I will be a restless wanderer on the earth, and whoever finds me will kill me.”

15 But the Lord said to him, “Not so[e]; anyone who kills Cain will suffer vengeance seven times over.” Then the Lord put a mark on Cain so that no one who found him would kill him. 16 So Cain went out from the Lord’s presence and lived in the land of Nod,[f] east of Eden.

'Whoever finds me' 'No one who found him' Indicates that there were other people at the time.

Land of Nod identifies a proper noun, Nod being the person who owns the land.

Not trying to be destructive, looking for good conversation. This deduction seemed obvious to me.