chicory escarole vs salad green

chicory escarole and salad green both are nouns.

Word	Noun	Adjective	Verb	Adverb
chicory escarole	Yes	No	No	No
salad green	Yes	No	No	No

As nouns, salad green is a hypernym of chicory escarole; that is, salad green is a word with a broader meaning than chicory escarole:

chicory escarole: variety of endive having leaves with irregular frilled edges
salad green: greens suitable for eating uncooked as in salads

Other hypernyms of chicory escarole include salad greens.

chicory escarole (noun)	salad green (noun)
variety of endive having leaves with irregular frilled edges	greens suitable for eating uncooked as in salads