  We present resistivity measurements of the upper critical field (H$_{c2}$)
phase diagram as a function of temperature (T) for
Nd$_{1.85}$Ce$_{0.15}$CuO$_{4+\delta}$/SrTiO$_3$ single crystal films with
different degree of disorder ($\delta$) in magnetic fields up to 90 kOe at
temperatures down to 0.4 K. The data are well described by a two-band/two-gap
model for a superconductor in the dirty limit.
