  An unquenched calculation of the form factor for $B\to D^* l \nu$ is needed
to improve the determination of $|V_{cb}|$. The MILC lattices, computed with a
2+1 improved staggered action for the light quarks, are well suited to this
purpose. The relevant staggered chiral perturbation theory (SChPT) must be
known in order to correctly account for the "taste" breaking discretization
effects associated with the staggered quarks to NLO in $1/ m_{D^*}$. This SChPT
calculation is presented.
