Your “Add Impulse” and “Set Collision Response to Channel” nodes try to read from hit events hit result but not when the actual hit happens. It will be null and that’s why you get an error.
Due to how blueprints work, you cant hop back and forth in time and expect values to be there, they are only there when the original execution wire on that path is live.
To fix that, you need to store the reference of the hit component into variable when the hit happens and then use that variable for your later actions.