"Nothing is easy."
Translation:कुछ आसान नहीं है।
I think it's actually the English that's idiomatic and confuses it. If you remove the negation, कुछ आसान है, there is an easy thing; नहीं है there isn't - ergo nothing is easy.
The phrase कुछ नहीं alone does mean 'nothing', but I suppose in Hindi, as in literally-taken English, using this order is saying that the absence of a thing is itself easy.
This probably arises because in English 'nothing' is a contraction of 'not one thing'; whereas कुछ नहीं is two words, and just plain negation, so as always नहीं comes just before the verb है।