Need advice on how to wire a switch outlet combo with two hot wires
Your description and comments are a little confusing, and your picture lacks detail, but I'll take a general swing at this. I think you want to swap this switch for a Leviton style switch/receptacle combo with the new switch controlling the existing receptacle(s).
Add white wire from the existing nutted white wires to the silver screw on the new device.
It looks like the wire from the top of the switch goes unspliced directly into a cable with two insulated conductors, if your existing receptacle is not a split duplex that cable normally would be a cable to the receptacle.
If you want the switch to control only the existing wall receptacle, and the half of the combo to stay hot then attach that top wire to the gold screw and the wire from the bottom of the switch to one of the black screws. There should be two black screws, it doesn't matter which one since you should be able to see they are connected together.
If you want the switch to control both the receptacle at the switch and the existing then attach the top wire to one of the black screws, and the bottom wire to the gold screw.
Add a bare wire to the ground screw.