chest vs body part

chest and body part both are nouns.

Word	Noun	Adjective	Verb	Adverb
chest	Yes	No	No	No
body part	Yes	No	No	No

As nouns, body part is a hypernym of chest; that is, body part is a word with a broader meaning than chest:

chest: the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates
body part: any part of an organism such as an organ or extremity

chest (noun)	body part (noun)
box with a lid; used for storage; usually large and sturdy	any part of an organism such as an organ or extremity
furniture with drawers for keeping clothes
the part of the human torso between the neck and the diaphragm or the corresponding part in other vertebrates
the front of the trunk from the neck to the abdomen