wonder child vs nestling

wonder child and nestling both are nouns.

Word	Noun	Adjective	Verb	Adverb
wonder child	Yes	No	No	No
nestling	Yes	No	No	No

As nouns, nestling is a hypernym of wonder child; that is, nestling is a word with a broader meaning than wonder child:

Other hypernyms of wonder child include child, fry, kid, minor, nipper, shaver, small fry, tiddler, tike, tyke, youngster, prodigy.

wonder child (noun)	nestling (noun)
a prodigy whose talents are recognized at an early age	young bird not yet fledged
	a young person of either sex