I think that nationalism as a term has been redefined by both alt-lite/paleocon/classical libs/whatever figures and the media in the run up to and after 2016. The new definition is the same regardless of the speaker. We've been hearing things like "the new political conflict is Nationalism vs Globalism". But when they talk about Nationalism, they're only really talking about Nation States as opposed to transnational government, and even then Nation State does not mean a state ran by the indigenous for the benefit of the indigenous, but just Civic Nationalism, Patriotism, Citizenism, whatever.
So when someone identifies as a nationalist nowadays it's not really clear if it's in the ethnic or "civic" sense. white nationalism is clearer but it's murky because it's a boogeyman term and there's two types of white nationalism, all whites welcome WN or separate white nations WN. Bannon and the like went with this economic nationalism thing but the term never really took off, but it's accurate in the Trump/Farage sense as it's all about TRADE TRADE TRADE with them.