I was baptized a Roman Catholic but confirmed Orthodox and I married a Greek Orthodox can I have my nephew baptized in a Catholic Church?
Since you are confirmed Orthodox and married a Greek Orthodox,
the Orthodox Church requires that any children you may have should
be baptized Orthodox.
Also, as an Orthodox, you are not allowed to baptize your nephew
or any other person in a catholic church. From the Catholic point
of view, unless your nephew is to be reared a Catholic, he may not
be baptized in the Catholic Church. If he is to be reared Catholic,
either by his parents or godparents, the Church will receive
him.
No you are GREEK orthodox u must not I reapeat not baptisma your
child at a catholic church.