However, you could choose from several transliterations, depending on how you want the name to sound and look:
Phonetic:
* نيك (Nik) - This is the most literal transliteration, pronounced "nik."
* نِك (Nik) - This adds a diacritical mark (shadda) to make the "k" sound longer.
More Arabic-sounding:
* نِكُو (Niko) - This adds the vowel "u" to the end, making it sound more Arabic.
Ultimately, the best way to write "Nick" in Arabic depends on your preference and the context.