Nigeria has a lot of potentials for business. With a population of over 150million people, it is the largest market in africa. Oppourtunities for profir are enormous, as regulating agencies and tax authorities are very lenient (except when they need a bribe from you!), however, the challenges involved are substantial. You have to generate your own power (electricity) as the public supply is practically non-existent, provide your own water supply (and still pay for having your own source of water because they government could not provide it), practically construct access roads to your factory, etc
Lest I forget, you must have your own police/army (prefarably OPC) to guarantee your security!

The challenges like the return on investment is enormous, so before you venture there, it will be a very good idea to go and live there for 3 to6 months to study the lay of the land. If you can survive it, you'll definitley be smiling to the bank (ask MTN Nigeria!)