I will give you my definition of a nation, and you can add the adjective 'Jewish.' A Nation is, in my mind, an historical group of men of a recognizable cohesion held together by a common enemy. Then, if you add to that the word 'Jewish' you have what I understand to be the Jewish nation.
Theodor Herzl (2014). “The Jewish State: with 2014 Foreword by Jerold S. Auerbach”, p.46, Quid Pro Books