«نشر الملك ألسنته في المدينة»
The king spread his tongues through the city.
If the intention is spies, “tongues” is an unsuitable figurative route to that meaning. Spying is more naturally associated with secret observation and intelligence gathering; Arabic usage therefore makes “eyes” (ʿuyūn) a clearer image for agents or spies.
«نشر عيونه»
He deployed his spies.
The example shows that substituting a bodily organ metaphorically does not suffice. The expression needs a recognizable association leading to the intended sense.