Can one find good pasteis de natas in the city?
Believe it or "nata"...their used to be a vibrant Portuguese community and a couple of delis on Bleecker Street (west side)...dunno if they even exist anymore.
Short of that, I'd hop the PATH for Newark (Ferry Street) or the LIRR to Mineola if you're unable to locate the goodies in Manhattan...or call Texeira's or Coutinho's Bakery and try for a distribution point from their wholesale operation! (Then tell me about it!).
Alas, the beautifully azulejos-tiled "O Padeiro" on 6th Avenue & 19th Street is history...they had 'em.
IMHO, the honor of "best nata" goes to Teixeira's Bakery in Newark. Creamy, sweet filling and buttery, crisp shell--all perfectly and ever-so-slightly burnt/caramelized on top. And a bargain at only 75 cents. Undoubtedly the best this side of the Tagus--and much better than most I had on a recent trip to Portugal. If you're feeling adventurous, they have other "pastel" varieties: lemon, coconut, orange, almond, and green bean (!). FYI, "O Padeiro" was Teixeira's incarnation in Manhattan. You can still get the stuff you miss if you're willing to travel. Bom apetite!