Ich esse keine Orangen.
I translated this sentence as "I eat no oranges", which was accepted as correct. I saw that "I do not eat oranges" is also correct. I though nicht negates a verb, while kein (or keine) negates a noun. While the sentences mean the same thing (or very close), why did this sentence use keine rather than nicht?
It depends on how literal you want the translation to be. "I do not eat oranges" has the same meaning (more or less) as "I eat no oranges". Duolingo allows both translations for cases like this, usually, although I have been frustrated from time to time, when I use a more natural or colloquial translation for something, and Duolingo marks it wrong.