Is my organization eligible to file a 990-N postcard return?

This depends on several factors, but per the IRS website:

https://www.irs.gov/charities-non-profits/annual-electronic-filing-requirement-for-small-exempt-organizations-form-990-n-e-postcard

Your chapter should only file a Form 990-N postcard return if eligible to do so per IRS guidelines.  

Avoid the mistake of underestimating your chapter's gross annual receipts by

verifying before you complete the 990 report on Vault:

How do I verify my organization’s gross receipts for the tax year?