White nationalist/nationalism is not a new term. It goes along with white separatist, white supremacist, and white pride/power. (Also, found amongst these are neo-Nazi/national socialist organizations, other Aryan identity groups, a particular form of Traditional Catholicism (different from Roman Catholicism) that focuses on race/ethnicity, & Christian Identity (different from Christian churches) groups.) Groups for white nationalism have been in existence for at least 10-15 years. They just haven’t been recognized by most national media because they used to be on the fringes of the political world. Like other supremacy movements, it began to grow after Barack Obama’s first election.
If I remember correctly, the group League of the South falls under either white nationalism or white separatism.