The 1860 census reports N. J. Chance as a blacksmith living on Valetta Ranch, Denton County TX. As a blacksmith he would have been quite valuable as a member of any mounted command.
The 1870 census for Lawrence County MO lists daughter Texas as five years old and sons Jefferson D. and Robert E. L. as seven years old. Who could the boys have been named after???
All were born in Texas, but daughter Alabama, age one, is reported as born in Arkansas.
Thirty is above average for a Confederate soldier, but conscription laws passed by Congress between 1862 and 1864 required service of most white males betwen the ages of 17 and 50, the initial age range being 18 to 35. I would venture to say that both service files represent the same man. Copies of these service files are available here.