Scout sounds like an endearing nick name. You could use it no matter what the child's official name is.
I think of the nick name
Tad when I hear the name
Thaddeus.
I don't think that nick names always have to be closely related to the given name.
My grandfather's name was
Duane Martin but as a child everyone called him Zeek. Later people called him Mart and as an adult he was called
Van.