nail down vs settle

nail down is not a noun while settle is a noun.

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

As verbs, nail down and settle are synonyms defined as:

nail down and settle: make final; put the last touches on; put into final form

Other synonyms of nail down include finalise, finalize.

nail down (noun)	settle (noun)
	a long wooden bench with a back

nail down (verb)	settle (verb)
make final; put the last touches on; put into final form	take up residence and become established
define clearly	form a community
succeed in obtaining a position	become settled or established and stable in one's residence or life style
	establish or develop as a residence
	make final; put the last touches on; put into final form
	become resolved, fixed, established, or quiet
	come as if by falling
	bring to an end; settle conclusively
	settle conclusively; come to terms
	end a legal dispute by arriving at a settlement
	come to terms
	accept despite lack of complete satisfaction
	get one's revenge for a wrong or an injury
	fix firmly
	arrange or fix in the desired order
	come to rest
	settle into a position, usually on a surface or ground
	cause to become clear by forming a sediment (of liquids)
	sink down or precipitate
	go under
	become clear by the sinking of particles
	dispose of; make a financial settlement