"Nationalism is consistently an ideology of World Order".
[Paul Treanor, Nation Planet]

Nietzsche sees all politics as a means to an end; therefore, political movements are a Becoming, a Process, to be variously modified and cast-off when the time arises. Likewise, the s expected their political party to become irrelevant once their goals had been attained; and amongst the ancient Romans the Dictator was entrusted with power in times of crisis, and expected to retire when the crisis was over.

Modernism is a Crisis.

"National bigotry is one of the most favourable inhibitions and remedies of Modernity, as it simplifies, it concentrates".
[Nietzsche, WzM 126]

Here Nietzsche advocates the extreme form of Nationalism, so necessary in an age where all is weak, tolerant, and overly-complex; where all lacks focus.
Nationalism is a duty for those Nietzscheans living today if they actually want to see something DONE;

"Through the interposition of the virtues of;
Obedience,
Duty,
Patriotism, and
Loyalty,
Through upholding
Pride,
Strength,
Hatred,
Revenge - in short, all typical characteristics that contradict the Herd Type, does the State do a host of things that the individual would never countenance".
[Nietzsche, WzM 717]

That last sentence is important; there are things - necessary things - which the 'individual' cannot do. In times of Degeneration, individualism is surrender, is defeat, is Nihilism.

Yes, my timid ones, today we need those virtues which include Hatred and National Bigotry!

We need this Nationalism to create Greatness; it will be noted that liberal democratic internationalist politics does not create greatness - quite the opposite!
"A nation is a detour of nature to arrive at six or seven great men. Yes, and then to get 'round them".
[Nietzsche, BGE 126]

Greatness is always within the vicinity of Nationalism;
"Napoleon made nationalism possible: that is its excuse".
[Nietzsche, WzM 877]

We never make absolutist claims for Nietzsche; we say rather that here and now, Nationalism is Necessary - anything else is cowardice.