Congress specifically exempted him and only him from direct access to the various superweapons (nuclear, chemical, and viral) that the US has in stockpile, during his last term. That still applies. He has to get permission from Congress and/or the Joint Chiefs to use them
https://www.npr.org/sections/insurrection-at-the-capitol/2021/01/08/955043654/pelosi-asks-military-to-limit-trumps-nuclear-authority-heres-how-that-system-wor
I don’t know if it passed, but I seem to recall that it did