The cytoplasm houses all the organelles of the cell. In fact,
save the nucleus, all the organelles are part of the cytoplasm.
They themselves contain it. (The nucleus has its own substance -
karyoplasm).
Nonetheless, you could say the nucleus was IN the cytoplasm.
Mitochondria, lysosomes, peroxisomes, chloroplasts, glyoxisomes
and nuclei are all found in the cytoplasm --- as are all the other
organelles in existence.
:)