You can use the cheat console command to execute any cheat, e.g. "cheat shazam" should work, so you could then bind that to an input event, as vermil suggests:
bindevent key-m-down "cheat shazam"
Another option is to "give" (console command) yourself the tomb of power (also bindable).
Comments
How can I bind "shazam" to a key (X)?
The problem is that, to my knowledge, there is no console equivalent to the Shazam cheat in Dday.
Another option is to "give" (console command) yourself the tomb of power (also bindable).