I am a Nigerian living in Nigeria.
I intend to travel to Fiji Island. I was asked to get a Brazil transit visa.
Secondly, do I need to get an invitation letter from someone residing in Fiji to be able to travel there?
United's version of the Timatic software/database states that you do not need a visa for Fiji but you should have evidence of onward travel.
You also will need:
Vaccination against yellow fever required if arriving within 10 days after leaving or transiting countries with risk of yellow fever transmission.
The Fijian Embassy in Washington D.C. sums it up nicely:
Requirements for Applicants from Exempted Countries
- A valid passport that does not expire within 6 months from the date of departure from Fiji
- Return air tickets showing the date of departure from Fiji or the country of your next visit
- Proof that you have enough funds for your travel to Fiji in the form of a bank statement (translated in English)
If your are transiting in Brazil ON THE SAME TICKET, you do not need a visa. If you have separate tickets, you will need a visa.