This year, I started working for an international organization under a non-us passport (dual-nationality). Is there anything I need to keep in mind while filing taxes?

[KarenJ2]

 If you are a U.S. citizen working in the United States for a foreign government or international organization, you must report this compensation as wages on Form 1040 and pay self-employment tax on the compensation under the Self-Employment Contributions Act (SECA).

Although you are subject to self-employment tax on this employee compensation, you are not "self-employed" for any other federal tax purposes. You may not claim deductions for expenses on Schedule C and are not qualified to establish a Simplified Employee Pension (SEP) Plan and there is no allowable deduction for contributions to any such plan. 

Employees for International Organization - How to Report Compensation