I don't use the word chief as a nickname. But if I did it would be for a specific reason and it wouldn't be interchangeable with "dude". Most likely it would be a term of respect or deference. If I called a friend or colleague "Chief" in earshot of a Native American and he was offended and called me out, I would probably apologize and I would avoid doing it again until he was gone. But I would not feel bad and it would not stop me from referring to that person as "Chief" in the future. I would simply avoid doing it around him as a courtesy. Regardless, how could he know the context of my use of the word "chief"? I could be talking to my boss. There are plenty of examples in popular culture of the use of the word "chief" as a nickname that have nothing to do with Native Americans.

1. Get Smart

2. Fox and the Hound

3. Gimme a Break

4. Battlestar Galactica

5. Doom Patrol

As far as your demeanor, you admit in your first paragraph that it's "hard to be civil", but in your second paragraph you say that you were simply being argumentative. Which is it? I mean, you basically called me an asshole.