Hello and welcome.
First off, let me start by saying that any alleged "portuguese-galician" or "luso-galician" identity is false. Within the framework of Spain (or Hispania/Iberia), the Galicians have
some especial relation to the Northern Portuguese. But they have no especial relation whatsoever with the people farther south of the Dorum (Douro, Duero) river.
Which takes me to reverse your question: the self-called "Portuguese nationalists" defend a people as ethnicacally diverse as are the Northern Portuguese (formerly known as Galaecia Braccarensis and Condado Portucalensis) from the Central and Southern Portuguese, and call it a nation... isn't that ironic?
Further to this, the basis for this so-called "nation" is in fact the dominions of a king, which were ceded to his ancestor as a county by the
Imperator Totius Hispaniae (the King of Leon).. or, in other words, the basis so this so-called "nation" is no less than... a state!
The pre-origins of this state are in the division of the Spanish nation (Spania) which achieved its ethnogenesis from the Lusitania to the Tarraconensis and from the Salto Vascorum to the Betica in the reigns of Leovigildo and his son Recaredo, through the judicial, territorial and ethno-racial union of Leovigildo which crystalized with the religious union of Recaredo.
The origins of this state are clearly in the chaos derived from the Muslim invasion.
And yet all of this, you would call such state.. a nation? Let me quote the Castillian poem of El Cid:
Cosas veredes que faran fablar las piedras 
__________________
'Dardanidae duri, quae uos a stirpe parentum
prima tulit tellus, eadem uos ubere laeto
accipiet reduces. Antiquam exquirite matrem:
hic domus Aeneae cunctis dominabitur oris,
et nati natorum, et qui nascentur ab illis.'
We can easily forgive a child who is afraid of the dark; the real tragedy of life is when men are afraid of the light.
–Plato–
'Many people, I believe, wish for a society where faith, decency, pro-life convictions and national self-determination within Europe can flourish; and not be swallowed up in a dictatorial EU bureaucracy.'
–Gerry McGeough, Irish Nationalist and POW–