From Wikipedia's article on Carlism:
"Dios, Patria, Fueros, Rey"
These four words (which can be translated as God, Fatherland, Local Rule and King), have been the motto and cornerstone of Carlism throughout its existence. What Carlism understood by this was:
"Dios" (God): Carlism believes in the Catholic Faith as a cornerstone of Spain, and must be politically active in its defense.
"Patria" (Fatherland): Carlism is heavily patriotic, but not nationalist. Traditionalism sees the Fatherland as the nesting of communities (municipal, regional, Spain) united under one.
"Rey" (King): The concept of "national sovereignty" is rejected. Sovereignty is vested on the King, both legitimate in blood and in deeds, who effectively rules. But this power is limited by the doctrine of the Church and the Laws and Usages of the Kingdom, and through a series of Councils, traditional Cortes and state-independent intermediate bodies. The King must also be the Defender of the Poor and Keeper of Justice.
Fueros: Somehow similar to charters. Part of the limitation of royal powers is the acknowledgment of local and regional self rule (and of other types of communities in the political body, specially the Church). Although the result of a peculiar historical development in Spain, it converged with the concept of subsidiarity in Catholic Social Thought.
I highlight the definition of "Patria" because it is one I agree with. As much as I agree with Gral Franco on many things, I disagree totally with his betrayal of the Carlists on this point and his acceptance of the Revolutionary doctrine of Nationalism. Nationalism has been the death of local, Catholic cultures in the Catholic countries of Europe, ever since the Revolution.
The "nationalism" of the Austrians was somewhat different, in that it was in a small homogenous country and was a reaction to the pan-German "nationalism" of Hitler's brown socialists.
Extreme nationalism can easily give rise to racism. Vide the refrain of la Marseillaise, the anthem of red, revolutionary France:
To arms, citizens,
Form in battalions,
Let impure blood
Water our furrows!
For a Catholic, or indeed any Christian, to talk of "impure blood" is blasphemy, since we are all related through our descent from our First Parents. Indeed, the great Christian Monarchies seldom contained only one "nation" or language/culutural group. France had both the langue d'oc and the langue d'oil as well as the Bretons and the Gascons (Basques). Spain had the Catalonians and Castilians as well as the Basques (Gascons). The pre-WW I Austro-Hungarian Empire, of course, had so many I will not try to list them all, but they included Germans, Magyars and several Slav nations as well as groups forgotten by all but themselves and historians of the Empire.
St Istvan, the first Christian King of Hungary, in his testament to his son, said that it would be a sad thing to rule over a kingdom of one nation.