Exporting to Nigeria is not a complex matter.
Due to risk factors letters of credit are not normally advanced to anyone by most companies until a B2B arrangement is firmly established or if it is a government parastatal .
To export to Nigeria where you are selling directly to a distributor, or importer, they will already have a variety of different elements in place to clear their own goods.
I ship to this country regularly, I never get involved in good clearance. I ship FOB and that is most practical buyer pays the stipulated shipping, organises their own shipping and clears their own goods.
This is because I am not physically on ground and it is impractical to attempt to remotely facilitate this process
With regard to busines terms you should ordinarily obtain a minimum of 30% up to 70% to accept fulfilment of order and 100 % of your goods costs should be obtained before you let your goods out of your sight.
A fair number of responses are citing shipping capability and advise on shippment, but I assume you just want to know what to do practically.
So again the rules are
1. No payment, no shippment unless credit lines are earned and be wary of credit line agencies who will gain credibilty and then default on larger shippings
2. no less than 45% must be recieved before production
3. Do not accept any cheques or banking drafts use Bank transfers only
4. Do not get completely strung into 'helping' the recipient to clear goods, it is rare to do CIF to Nigeria. Just sell FOB
5. If you decide to set up warehousing there, then take a month out go there and set your instruments in place.
Hire a car and driver for the duration, book into an apartolodge and take all your credentials with you ideally to Abuja.
Seek collaborations or technical liasons where possible to fulfil your aims.