You appear to be talking about meiosis. Meiosis is different from the more common cell division cycle mitosis in that meiosis involves two sequential cell divisions. The four basic phases of meiosis/mitosis are prophase, metaphase, anaphase, and telophase. Of these four, telophase is the phase where the separated chromosomes are enveloped into two new nuclear membranes to create two new nuclei. Also, the cell prepares for cytokinesis, which is the following stage where the cell actually splits into two new cells around the newly formed nuclei. Since meiosis involves two sets of cell division, you could be talking about both telophase I and telophase II.