You can’t actually combine Nationalism and Socialism as Socialism is directly opposed to Nationalism. Mussolini went over this many times how “It is an error of Socialism to exclude Nationalism”(paraphrased), the Socialist aspect is reduced to the future where the “others” have been eradicated, which will never actually happen as Hitler went from “There are 5 white races” to “All Mediterraneans have been negrified” and I’ve no doubt he would eventually consider all slavs to be “mongolized”.