Nato make it a part of final phase (5)
I believe the answer is:
alpha
'nato make it a part' is the definition.
I can't judge whether this definition defines the answer.
'of final phase' is the wordplay.
'of' indicates the answer is hidden within the clue.
'ALPHA' is hidden within 'final phase'.
Can you help me to learn more?
(Other definitions for alpha that I've seen before include "First, best quality" , "First in order of importance (for a Greek?)" , "Leading Greek character" , "Most prominent star" , "Dominant" .)