I believe that PSLF applies to 501(c)(6) organizations, but I was curious whether or not it would apply to a chamber of commerce.

The only kind of non-profit that automatically qualifies for PSLF is a 501(c)(3).  For 501(c)(6)‘s, it depends. 

The Department of Education will need to make a determination of whether the specific nonprofit qualifies as a “Public service organization”.  Public service organization is defined as:
(5) A private organization that—
(i) Provides ... [specific listed services including “legal services funded in whole or in part by a local, State, Federal, or Tribal governments”]; and
(ii) Is not a business organized for profit, a labor union, a partisan political organization, or an organization engaged in religious activities, unless the qualifying activities are unrelated to religious instruction, worship services, or any form of proselytizing.

I suggest you look at the full list in the regs of the specific services that qualifying public service organizations provide.  The PSLF regs are under Student Loan Laws at http://askheatherjarvis.com/tools  If you are looking to fit into the legal services category, you’d need to confirm that the org gets some government funding, which they may or may not.

Also, you can make your case for qualification to using the Employment Certification process described here:  http://askheatherjarvis.com/blog/3-new-documents-everyone-in-government-and-nonprofit-services-needs-right-n

Hope this answers your questions.

Kind regards,
James Jarvis
Communications Director
Heather Jarvis, Student Loan Expert LLC