Okay kiddo, so a long time ago in Germany there were some people who were born into really rich and fancy families, and they were called nobility. They were kind of like princes and princesses, but not exactly.
Then a guy named Adolf Hitler came around and started a political party called the Nazi party. He wanted to be in charge of Germany and do some really bad things to people who were different than him.
Now, some of these nobility people who were in the Nazi party thought it would be a good idea to join in with Hitler and support him. Maybe they thought they could keep some of their power and influence that way, or they agreed with some of the things he was saying.
But being a part of the Nazi party was not a good thing, because they did really awful things like hurting and killing millions of people, especially Jewish people. So, it was not okay to be a part of this group and support them.
That's basically what it means, kiddo. Nobility people were in the Nazi party, but it was a bad thing to do because the Nazi party did bad things to people. We should always try to be kind to everyone, no matter who they are or where they come from.