Once you know you owe an annual return — whether as a PAYE employee or a freelancer/informal-sector earner — the next question is where to actually send it.
Most people file with their State Internal Revenue Service (based on where you live, not where you work) — not the NRS. The NRS's own self-service portal is only for armed forces, police, Foreign Service staff, and non-residents.
TaxLane's in-app "Find where to file" panel has a direct portal link for 35 of Nigeria's 37 states and territories — for the rest, it links out to the Joint Tax Board (https://www.jtb.gov.ng/), the national body coordinating all State IRSs.
Every TaxLane calculator result includes a "Find where to file" panel with a state picker — select your state there for its direct portal link or contact.
No — for guidance only, not tax advice.