nail down vs determine

nail down and determine both are verbs.

Word	Noun	Adjective	Verb	Adverb
nail down	No	No	Yes	No
determine	No	No	Yes	No

As verbs, determine is a hypernym of nail down; that is, determine is a word with a broader meaning than nail down:

nail down (verb)	determine (verb)
make final; put the last touches on; put into final form	reach, make, or come to a decision about something
define clearly	fix conclusively or authoritatively
succeed in obtaining a position	shape or influence; give direction to
	fix in scope; fix the boundaries of
	establish after a calculation, investigation, experiment, survey, or study
	find out, learn, or determine with certainty, usually by making an inquiry or other effort
	decide upon or fix definitely
	settle conclusively; come to terms