  We present results for the selfenergy of the $\Theta^+$ pentaquark in nuclei
associated with two sources: the $KN$ decay of the $\Theta^+$ and the two meson
baryon decay channels of the $\Theta^+$ partners in an antidecuplet of baryons.
The first source is shown to produce a small potential, unable to bind the
$\Theta^+$ in nuclei, while the second source gives rise to a large attractive
potential. At the same time we show that the width of the $\Theta^+$ in nuclei
is small, such that, in light and medium nuclei, many bound $\Theta^+$ states
would appear with a separation between levels appreciably larger than the width
of the states, thus creating an ideal scenario for pentaquark spectroscopy in
nuclei.
