By that definition the "Nation" is the area under the jurisdiction of our sovereign government. Oops!
In all of this, what Art 1, 2 & 3 do now is remove the authority of the State to enact and administer laws in the territory of NI and instead bestows such a entitlement to all of the people born (save 27th amendment) to determine the political and economic future in whatever form they choose. Currently, that is in the form of two separate States, one governed by a foreign State.
Double Ooops!
The Irish nation, in its entirity, has chosen a political settlement that facilitates those who choose to remain under British jurisdiction.
It is open to all of us to revert back entirely under British rule, to unify the country as a sovereign independent state, to keep the partitionist status quo, or other.
It is open to all people of the Irish nation to determine our future
Perfectly compatible with the Constitution