Alexis’s viewInsecurity was a major issue during Nigeria’s 2015 election, my first as a Reuters correspondent there. It still is today, ahead of presidential polls in January — on a far larger scale, with implications for the country’s economy greater than ever before.That 2015 election is significant because it was held a year after nearly 300 girls were abducted from a school in the northeast Nigerian town of Chibok by jihadist group Boko Hara…