A tempest in a teapot.
It wouldn’t make strategic sense for Israel to nuke Gaza because they hope to populate it with Jews in the near future (and the New Gaza Jews wouldn’t want their babies to glow in the dark).
Makes sense that such a statement would be bravado. But the Hamas/Iran gang could use it as an excuse to attack. Some poster here on FR suggested that Netanyahu told the minister to say it. Because Israel wants to be attacked so they can get intelligence, or see how they would react to such a statement? Who knows.