Contemporary examples include the Philippines, Hungary, Poland's Law and Justice Party, and arguably Russia, Turkey and India. Modi is a Hindu nationalist. The United States unfortunately is shaping up to count as an example as well.
Extreme forms of nationalism tend to have a narrative of grievance, a desire to restore a once a great national identity, and a tendency to divide the world into loyal citizens, and enemies without and within, against whom authoritarians powers must be mobilized.
So there's a conceptual basis, in terms of setting the stage for rationalizing authoritarianism, as well as abundant historical examples demonstrating the marriage of nationalism and authoritarianism in action. There's nothing wrong with not knowing, but I would say there's an extremely strong and familiar historical canon to those who study the topic.
