nurse vs do by

nurse is a noun but do by is not a noun.

Word	Noun	Adjective	Verb	Adverb
nurse	Yes	No	Yes	No
do by	No	No	Yes	No

As verbs, do by is a hypernym of nurse; that is, do by is a word with a broader meaning than nurse:

Other hypernyms of nurse include handle, treat.

nurse (noun)	do by (noun)
one skilled in caring for young children or the sick (usually under the supervision of a physician)
a woman who is the custodian of children

nurse (verb)	do by (verb)
try to cure by special care of treatment, of an illness or injury	interact in a certain way
give suck to
maintain (a theory, thoughts, or feelings)
serve as a nurse; care for sick or handicapped people
treat carefully