While playing, my kid said "ich hau dich, du Nuss". What does it mean in English?
A literal translation is "I (will) hit you, you nut!".
That's also a quite close to a correct translation of the content.
Note that "Nuss" (literally "nut") is used here as a mild, non-specific insult, possibly implying mild stupidity. It does not mean a crazy person.