My bad! Just googled an image of the A270, I didn't realize it was an external mix airbrush, and yeah the nozzles I posted wouldn't help you. Now that I've researched it a bit better you might try contacting Testors directly:
Testor Corporation
440 Blackhawk Park Ave.
Rockford, IL 61104
Questions regarding parts may directed to our Customer Service Department at 1-800-837-8677 M-F 8:00 AM - 4:00 PM CT
I'm pretty sure the parts they're talking about is kit parts, but you never know...
I've also researched the cost of a replacement airbrush, and WOW are they expensive for what you get $49.99 for the A270-5 set with hose, adapter and instruction video(?).
For not a lot of money you can buy a Badger 350 which is also an external mix, but comes with metal air and paint nozzles, it's only $29.95 US at Dixie Art. Double that money and you can get a "professional" quality from Badger, Iwata or Paasche. They would be a considerable improvement in quality over the A270 Testor and are built out of much better materials.
Good luck!