Do I Need to File Personal Income Tax Returns in Niger State If My PAYE Tax Is Already Deducted From My Salary in Nigeria?

Filing annual returns is different from paying tax.
Paying tax is what your employer already does under Pay As You Earn where tax is deducted from your salary and sent to the tax authority.

Filing annual return, on the other hand, is you officially declaring your total income for the year and confirming that the tax deducted by your employer is accurate.

So even though your tax has been deducted at source, filing annual returns still serves as a form of personal record and compliance.
because It helps the tax authority confirm your income, and it also protects you in case there is ever a need to verify your tax history, apply for loans, visas, or other financial processes.

For example:
imagine Mama Ngozi sells tomatoes and her assistant collects a small tax from her sales daily and sends it to the market authority. At the end of the year, Mama Ngozi still goes to declare her total sales and confirm that all the deductions made on her behalf are correct. She is not paying again, she is simply reporting and confirming her records.

So your understanding is right that filing returns is about declaring and documenting, not necessarily paying again if tax has already been deducted. However, in practice, many salary earners rely on their employer to handle most of this, but it is still a good habit to file your annual returns if required, especially for proper financial record keeping.

Because.. Filing returns helps you stay compliant, organized, and financially transparent, even when your tax has already been deducted at source.