Yeah there's a bit of a change in meaning between nation and nationalism - like a moral camouflage, but especially subtle. Nations are great. We need more nations. But nations disappear under nationalism, which is just a justification for a state that's larger than a nation. 

Take France, for example. Its the first modern nation state, and had the first mass fervor for nationalism in the French revolution. Before that, it was a feudal hierarchy of duchies, which were distinct enough to call them nations. The king had separate contractual obligations to each feudal subject. People from Champaign probably had a hard time understanding the speech of someone from Gascony, and same for Bretonny and all the rest. These places were basically nations within a state. After the revolution, the state needed something to legitimize its bloated criminal existence, so it invented "frenchness" and literally stole children from their parents to isolate them in a school that taught Parisian French, to wipe out local identity. Nations died for the sake of nationalism.