Those humanoids with proper insulation such as Green Lantern, Magneto, or the Juggernaut could defeat a lightning of electrical foe. Superman's anatomy is humanoid(kryptonian) and--as long as he isn't properly insulated or has a shield--lightning says to him, "I'm an assassin who's going to kill you easily; you're not so tough." Superman never backs down and, as is the case with an assassin's bullet hitting a person, Superman is dead or TKO'd permanently!
Lightning stops the heart and potentially the brain with relatively small amounts of electricity in comparison with the voltage in an actual lightning bolt. So, if a hero or villain can either take advantage of his no kill policy(Storm: for which she can then do what she did to Sabertooth in the train station AND in a well written comic book that would be a kill for a humanoid) or take an electrical form(Electro, Livewire, and the Living Lightning would win easily if Superman could not very, very quickly counteract their energy forms in a well written comic battle). In my opinion, a humanoid SUPERHERO would have a near impossible chance at defeating an electrical or lightning wielding foe due the humanoid's physiology!