Here's our staggering, overwhelming power, as Spider-Man or Batman? (9)
I believe the answer is:
superhero
'spider-man or batman?' is the definition.
'here's our staggering overwhelming power' is the wordplay.
'staggering' indicates an anagram.
'overwhelming' is an insertion indicator.
'power' becomes 'p'.
'heres'+'our'='heresour'
'heresour' is an anagram of 'suerhero'.
'suerhero' enclosing 'p' is 'SUPERHERO'.
'as' acts as a link.
(Other definitions for superhero that I've seen before include "person who catches lots of baddies" , "comic book creation" , "people didn't notice in Kent, for one" , "Batman, say?" , "I'm often seen in a cape" .)