Boko Haram has killed tens of thousands of people, including many Christians, as it attempts to set up a state ruled by Strict Islamic law.
On Saturday the group said it wanted to become part of IS, the group taking over large parts of Iraq and Syria.
Reports suggest the trucks carrying soldiers have been entering Nigeria since late on Friday night.
Locals in Bosso, close to Nigeria's north-east border, reported hearing gun shots and loud explosions, in what's seen as an escalation in the fighting between armed forces and the militant group.
Diocese of Jos spokesman Revd Canon Hassan John told Premier's News Hour the ground offensive against Boko Haram already appears to be gaining ground, he said: "Boko Haram have been put under a lot of pressure in the last couple of days, and quite a number of towns have been recaptured from Boko Haram."
Military bosses in Nigeria and Chad both declined to comment on the ground offensive.
There have been several reports of Boko Haram fighters killing Christians because of their faith and burning churches to the ground.
In February the group murdered more than 60 pupils at a Christian school in northern Nigeria.
Diocese of Jos spokesman Revd Canon Hassan John: