نِيُويُورْك

It doesn't have to be written with diacritics; it can be written without diacritics نيويورك, but if they want to use diacritics, this sign ْ on ن is incorrect here because it means there is no vowel between the ن and the constant after it which is not true here and words in Arabic can't begin with a constant without a vowel sound after it.