My impression of nationalism is not to disjoin the union of American states- although I do not undermine the value of that position.
In my opinion nationalism can refer to the community ties that are very much apparent (although strained in some areas) in the Black community- not necessarily the physical or political boundaries available.
To be truthful I dont think Black Nationalists will be satisfied in being separatists- we dont want a country of our own- we want this one.