Nichols is charged with 160 counts of first-degree murder for the 1995 federal building bombing that killed 168 people and injured more than 500.
State prosecutors plan to seek the death penalty.
A federal jury earlier convicted Nichols on federal involuntary manslaughter and conspiracy charges and he was sentenced to life in prison. The E.W. Scripps Co. Users of this site are subject to our User Policy and Privacy Agreement . Please read them.