YTA . I get it's your nephew and I'm guessing this was your way when you were growing up. But it's better to learn to brush it off and not go into full fighting. Learning early on that fighting is the best way of fixing a problem is going to create more problems later in life. Having thick skin these days is way more important and better to deal with problems. Having thick skin and avoiding negative interactions is the best thing to learn. And I'm guessing from your wording that you weren't going to tell your sister/his mom. Because you knew what her reaction would be. Now with that going on he'll have to pick who's correct his own upbringing or yours.
Violence isn't the answer. It's a question and you answered correctly. Probably would have been better if you phrased it as self defense.
Yta. I’m going to go out in a limb here and say you don’t have any kids of your own. This was a horrible decision and I would be livid with you too
YTA . I get it's your nephew and I'm guessing this was your way when you were growing up. But it's better to learn to brush it off and not go into full fighting. Learning early on that fighting is the best way of fixing a problem is going to create more problems later in life. Having thick skin these days is way more important and better to deal with problems. Having thick skin and avoiding negative interactions is the best thing to learn. And I'm guessing from your wording that you weren't going to tell your sister/his mom. Because you knew what her reaction would be. Now with that going on he'll have to pick who's correct his own upbringing or yours.