Actually, in a case of clear self-defense, the DA has the authority to decide whether it's even worth it to waste the taxpayers money in much of an investigation. Considering that Lex had kidnapped Lois and Clark, and was obviously trying to murder his wife, my guess would be that the DA would decline to press any charges at all. At the worst, it might be ruled a case of justifiable homicide, but more likely it would be ruled either self-defense or an accident, since Lois wasn't actually trying to kill him. She was simply trying to keep him from killing her.
Nan
