What are the visa & residency requirements in Nigeria?

"In order to visit Nigeria, travelers must obtain a visa prior to arrival. The process of applying for a visa involves submitting an application form, a valid passport, two passport-sized photographs, and a fee. Depending on the type of visa, additional documents may be required. In order to obtain residency in Nigeria, applicants must submit an application form, a valid passport, two passport-sized photographs, and a fee. Depending on the type of residency, additional documents may be required. Applicants may also be required to provide proof of employment, proof of financial stability, and a medical certificate. Once the application is approved, the applicant will be issued a residency permit," mentioned another expat when asked about moving to Nigeria.