“In return for Ukraine giving up the hundreds of nukes and delivery systems they had at the end of the Cold War”
I understand that the “nukes and delivery systems” legally belonged to the Commonwealth of Independent States, the legal successor to the CCCP.
If North Dakota declared independence, the USAF nuclear missiles in the state would remain under Pentagon control.
A Major Anderson[Fort Sumter] type officer would not let the North Dakota National Guard seize the missiles.
Of course, since Ukraine was a member state of the UN from the time of its creation and had its own ambassador casting votes just like the USSR, Ukraine had a presumptive and exclusive right to the nukes on its territory as a successor to the USSR of equal legal dignity with Russia and its subordinate provinces that compose the CIS.