Near through, you add, before daylight (7)
I believe the answer is:
tonight
'add before daylight' is the definition.
I can't judge whether this defines the answer.
'near through you' is the wordplay.
'near' becomes 'nigh' ('nigh' can be a synonym of 'near').
'through' means one lot of letters goes inside another (I've seen this in other clues).
'you' becomes 'tot' (I can't justify this - if you can you should give a lot more credence to this answer).
'nigh' placed inside 'tot' is 'TONIGHT'.
Can you help me to learn more?
(Other definitions for tonight that I've seen before include "after supper?" , "Got thin (anag)" , "song from West Side Story" , "later in the day" , "What succeeds this afternoon" .)