"Nigeria is a huge country. Parts of it—especially the northeast—are in an ongoing conflict, but it's important to have a very granular view on risk while keeping an eye on the big picture," said Tom Speechley, partner at The Abraaj Group, an investor in global growth markets.
Nigeria's newly revised annual gross domestic product now stands at $510 billion, making it a bigger economy than South Africa, whose GDP is $370 billion. Nigeria's annual GDP growth is 7.1 percent, according to the International Monetary Fund, outstripping other prominent economies of sub-Saharan Africa (see table).
Read MoreGunmen abduct 8 more girls in Nigeria; US pledges help
Militant group Boko Haram, which wants to create a strict Islamic state in Nigeria, claims responsibility for the abduction of almost 300 schoolgirls from northeastern Nigeria three weeks ago. Another eight girls were kidnapped on Tuesday. The group—whose name translates to "Western education is sinful" in the Hausa language—wants to limit Western influence in Nigeria, which comprises large Muslim and Christian populations.
"If Boko Haram ever decided to expand beyond their traditional base in the north and strike commercial targets in Lagos or the Niger Delta, it would have a very chilling effect on investor sentiment, in my view," Dr. Helima Croft, senior geopolitical strategist with Barclays commodities research group, told CNBC.