I had "Nac ydw" first, and it was translated "No, I don't." So I put "No, I don't, I don't want chocolate." and it didn't like it.
Duolingo is at its most fun when it comes up with these wild fantasy sentences.
I put, "No I don't, I don't want chocolate". Yet I got it wrong. It wanted "any" before chocolate. But the translation above doesn't add the word "any". Confusing to say the least!