Open Doors visited a Christian woman in a refugee camp where she lives with thousands of people.
As many as 3,000 people fled to neighboring Dori, where aid agencies are located, a local official said.
There has been a rise in crime and violence in Nigeria in the last two years.
The Jihad Analytics data also showed that while Nigeria has recorded 162 IS operations since January 2022, Iraq has recorded 120.
In late Fabruary, ISWAP already abducted three aid workers and two guards at a guesthouse in Cameroon.
ICC staff reviewed pictures of the man's body. He had knife wounds and one of his hands had been cut off.
Boko Haram has carried out 240 suicide attacks by women and female children since 2014.
Fourteen-year-old Halima Audo was captured by Boko Haram and imprisoned in a camp run by the Nigerian terror group.
On Friday evening, President Mohamed Bazoum announced the liberation of Boko Haram terrorists.