A nation without borders is not literally a nation. One could have a figurative nation such as the nation of artists or the nation of doctors that has no political boundaries .
An ethic group of people, perhaps displaced by war, living within the borders of some country or maybe several different countries might think of themselves as a nation without any exact borders.
Russia borders Finland.
The African nation that shares borders with Algeria, Tunisia, and Egypt is Libya.
Japan is an island nation without any borders.
Andorra is its own separate nation. It borders Spain and France.
Canada
Nigeria
nigeria
Mexico.
eritrea
Russia
Mexico borders the US on the south and Canada on the north.
Kampala is the capital and largest city of Uganda, the only landlocked nation that borders Lake Victoria.