how can archeaology be influenced by nationalism?

Yes, Hitler (Himmler actually) tried to use it to prove the superiority of the Arian race and to locate powerful religious symbols. Nazis were all about symbolism.

Archeology is just one of the many science nations have tried to use to either prove or disprove their theories. Athro, Biology, zoo-ology you name it it has seen some kind of influence from nationalism.

For better or for worse.

Check the link, it is actually pretty scary to think about.

Pretty easily, actually. It's called ethnocentrism, and it's a problem for even the most open-minded, careful archaeologists. People tend to believe that their culture is the best, and that the way they think is the way everyone thinks, or it should be. Modern archaeologists are aware of the problem, but that awareness doesn't mean necessarily that they'll not fall into the trap themselves.

Nationalism can do good things for archaeology- countries that are proud of their heritage tend to fund digs, which is good. But that pride can skew the interpretations of their findings. A major example of this would be back in the day in the US. When white Americans got far enough west to start encountering the mounds that earlier natives had built, they were surprised. Obviously, those savages could not possibly build such structures! Well, they did, really, but even today you'll hear about the "mysterious Moundbuilders of the Midwest". At the time, the US was basically at war with the natives, and national pride and the Manifest Destiny nonsense wouldn't allow us to look at the natives with anything approaching fairness.

I think it is called ethnocentrism or something, hopefully I am not mixing things up here. We all have different ways to think, some of it comes from us but some of it comes from social consciousness or something.... We believe certain things and apply them to certain concepts that does not equal... hmm....it could be related to some archaeological found in Italy about some chinese geishas (making it all up of course) and well Italians don't believe chinese came around well after, let's say 18th, so the Italians will 'change' the context and what not... hmm that's my take on it anyway