Question

When in mitosis would you see two nuclear envelopes forming around each new set of chromosomes?

Answer 1

Telophase is the answer

Answer 2

In telophase, which is the final phase of mitosis, when the chromosomes have been split, and the cell cytoplasm has divided, the nucleolus starts to form again, and everything else, including nuclear envelopes, re-form.

Hope this helps!