Nearly opening wee dram, perhaps later today (7)
I believe the answer is:
tonight
'later today' is the definition.
(I've seen this before)
'nearly opening wee dram' is the wordplay.
'nearly' becomes 'nigh' (synonyms).
'opening' indicates putting letters inside (some letters open a gap in others).
'wee dram' becomes 'tot' (I've seen this in another clue).
'nigh' put into 'tot' is 'TONIGHT'.
'perhaps' is the link.
(Other definitions for tonight that I've seen before include "late in the day" , "West Side Story number" , "What succeeds this afternoon" , "now or very soon" , "The end of today" .)