You must have completed a minimum of 30 or 32 course credits, which is comparable to one year of college course work, to transfer to NYU.
Although this is the minimum requirement, because you'll be a junior transfer student at NYU, I recommend transferring the maximum number of credits, which is 64.
Transferring as a junior will also save you a lot of money on tuition that you can use towards something else while still giving you an excellent experience.