Does Nationalism promote Racism ?

What's a "genuine Nationalist"? You omit examples.

Moreover, nationalism is, almost without exception, chauvinistic and intolerant of "multiculturalism", a by-product of objective internationalism.

As a rule, nationalism is antagonistic to multiculturalism.

It doesn't matter. At that point you are simply quarreling over different sides of the same coin.

You are trying to distinguish between "good" nationalism and "bad" nationalism. All I am saying is that when that occurs, it gets people all caught up in all that nonsense.
Nationalism- not "bad" nationalism- is what ruined Europe.

When you put the question categorically, the answer is: not necessarily. One can be a nationalist and not be racist. But generally speaking, nationalism posits that one group, a given nation, is somehow special, or better than other nations. That kind of in-group, out-group kind of thinking leads to all kinds of conflict and oppression, including racism.

I should add that at one time, nationalism was progressive. It is not any longer -- we are long past the historical stage that building separate nation states represents progress.

I'd say there are four basic ideas of nationalism that can be recognized, and of cource, they can all be mixed with one another.

1. Civic nationalism (also liberal nationalism) that is based of the feeling of beloning to a community (called "daily referendum" in liberal thought), which is basically "everything goes", whatever nation you want to create, go for it. Sometimes that separates people who speak the same language- like Germans and Austrians, or split of Yugoslavia; sometimes it makes people of different backgrounds and languages join together, in eg. American, Chinese of Swiss nation.
Problem here is that it can easily turn into ethnic or territorial nationalism, because a lot of people, when "feeling of belonging to a community" is concerned, that feeling can be defined by rase, tribe, dialect, region, religion.
Pure civic nationalism could be called "patriotism", but is very rare in it's pure form, because, as I just said- it's often mixed with ethnic and/or territorial nationalism.

2. Pan-nationalism is based of language, that is- mutual intelligibility. This is basically the only natural nationalism, in the sense of view that nations should form around mutual intelligibility, but it is extremly rare in pure form, it is also often mixed with ethnic and/or territorial nationalisms.

3. Territorial nationalism is based on "historical territories", that is- it's based on territory instead of people, and implies a wish to have territories that have been populated by some other nation(s) for some time, mostly because "they were sometimes ours", something like as if Greeks would want Asia Minor. Zionism is the best example, others are Germans wanting Alsace, Serbs wanting South Kosovo, Azerbaijanis wanting Nagorno-Karabakh, Argentina wanting Falklands etc. It implies a wish for some future wars in order to "take back" and "liberate" territories, or at least threats of war, or in the mildest (and the rarest) cases using political, economic and demographic means for "taking back" desired territories.

4. Ethnic nationalism is based of blood and origin and is opposed to mixing with other rases, nations, tribes, and is, like territorial nationalism, inherently oppressive and violent, because it implies a desire for limiting someone's movement (immigration) because of their blood, a desire for expulsion (or in worse case- killing) of peole because of their blood, as well as telling people they cann't marry and have children (or even socialize, or trade) with someone because they are of different of rase, nation, or tribe.