Answer:
Well, the nucleus of a cell in interphase tends to have less condensed chromosomes; the nucleus of a cell in mitosis (in particular during Prophase) has more condensed chromosomes. In other phases of mitosis, the nucleus is non-existent, except for telophase.
In other words, in interphase, you have euchromatin (less condensed chromatin), and in mitosis, you have heterochromatin (more condensed chromatin).
