In a February 2017 article in The Atlantic journalist Uri Friedman described "populist economic nationalist" as a new nationalist movement "modeled on the ' populism ' of the 19th-century . President Andrew Jackson " which was introduced in Trump's remarks to the Republican National Convention in a speech written by Stephen Miller and Steve Bannon. Miller had adopted Sessions' form of "nation-state populism" while working as his aid.  By September 2017, Greg Sargent, a journalist with the Washington Post observed that "Trump's nationalism" as "defined" by Bannon, Breitbart , Miller and "the rest of the 'populist economic nationalist' contingent around Trump", was beginning to have wavering support among Trump voters. 
1840, "exaggerated, blind patriotism," from French chauvinisme (1839), from the character Nicholas Chauvin , soldier of Napoleon's Grand Armee, notoriously attached to the Empire long after it was history, in the Cogniards' popular 1831 vaudeville "La Cocarde Tricolore."
Meaning extended to "sexism" via male chauvinism (1969). The name is a French form of Latin Calvinus and thus Calvinism and chauvinism are, etymologically, twins. The name was a common one in Napoleon's army, and if there was a real person at the base of the character in the play, he has not been certainly identified by etymologists, though memoirs of Waterloo (one published in Paris in 1822) mention "one of our principal piqueurs , named Chauvin, who had returned with Napoleon from Elba," which implies loyalty.
Nationalism is not to be confused with patriotism. Both words are normally used in so vague a way that any definition is liable to be challenged, but one must draw a distinction between them, since two different and even opposing ideas are involved. By ‘patriotism’ I mean devotion to a particular place and a particular way of life, which one believes to be the best in the world but has no wish to force on other people. Patriotism is of its nature defensive, both militarily and culturally. Nationalism, on the other hand, is inseparable from the desire for power. The abiding purpose of every nationalist is to secure more power and more prestige, not for himself but for the nation or other unit in which he has chosen to sink his own individuality.