Is there a coffee shop or cafe in or just outside of Union Square Station?

There is a coffee shop (called "Coffee Shop) on 16th Street and Union Square West; Chat n Chew on the same block. There are fast food shops on 14th Street.

If you want coffee, pastry, sandwich, wrap, hot pizza, or a hundred other choices, go to Whole Foods right at the station on 14th Street between Broadway and University. There is a ton of choices (self service), pay for your purchases; seating upstairs is plentiful.

http://www.wholefoodsmarket.com/stores/unionsquare...

There is also a coffee shop on 16th Street and Park across the park from the 16th Street exit at Union Square; a self-service pastry, soup and coffee place on Fifth and 15th - a block from the station.