“Nationalism” is a term which has come to have a rather ambiguous meaning. According to Merriam-Webster, it means “loyalty and devotion to a nation; especially a sense of national consciousness exalting one nation above all others and placing primary emphasis on promotion of its culture and interests as opposed to those of other nations or supranational groups.”
However, one has to then ask what is meant by a “nation.” We tend to think of a nation as “a sovereign state”, but I believe it is historically more correct to think of it as a homogeneous collection of “peoples”, in the Biblical sense; i.e., the Jewish Peoples, as opposed to the Jewish state of Israel, which incorporates many non-Jewish residents. A “nation-state“, in contrast, is a state consisting of one and only one, usually ethnic, nation. “Patriotism” can apply to either the nation or the state, or even a high school or college, I guess.
You can argue whether either one is a good thing or a bad thing, or what precise definition you want to go with. Personally, I consider the US to be a state, but not a nation as in “one nation under God.” It is a state consisting of a number of intermixed, but not necessarily compatible, national groups.
I study a lot of world and US history. I could be wrong about this, but I don’t think you can show me ANY state, EVER, that has included more than one nation and not had mutual hatred, or at least discomfort, in the mixture. I think that Abe Lincoln must have understood this when he proposed sending the freed slaves to either Liberia or South America. Mexico started out, after Columbus, with a mixture of Spaniards and Native Indians, and there was tremendous bloodshed between the two national groups. Eventually, over centuries, they intermarried and assimilated, and the Mexican People are now essentially an authentic People, or Nation.
Sad to say, I don’t think the US will ever get to that point. Because we are all, black or white, fallen, sinful, human beings, we will never get beyond the hatreds that now rack America, and this division is one reason the US is not mentioned, and will have no significant part in, the end-times events prophesied in scripture. To put it another way, by bringing slavery to America, we assured our own eventual destruction.
The Back of My Mind 
This was really good–with a dramatic ending! I was just reading something today by Alexander Maclaren in regard to the statue dreamed of by Nebuchadnezzar. Your post made me think again of what he said. This was a part: “The singular amalgam of iron and clay in the fourth kingdom is worth notice. No sculptor or metallurgist could make a strong unity out of such materials, of which the combination could only be apparent and superficial. The fact to which it point is the artificial unit into which the great conquering empires of old crushed their unfortunate subject peoples, who were hammered, not fused, together.” He concludes that “there is only one kingdom which has no disintegrating forces lodged in it, because it unites men individually to its king and so binds them to one another.” There really is no great future for America.