Source of power is ambiguous, following Nationalist uprising (7)
I believe the answer is:
nuclear
'source' is the definition.
(I have seen 'source of energy' mean 'nuclear' so perhaps 'source' could also mean 'nuclear')
'power is ambiguous following nationalist uprising' is the wordplay.
I cannot really understand how this works, but
'power' could be 'ear' (ear is a kind of power) and 'ear' is present in the answer.
'nationalist' could be 'n' (abbreviation in politics) and 'n' is located in the answer.
This may be the basis of clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for nuclear that I've seen before include "Relating to part of atom" , "Possessing atomic weapons" , "type of power supply" , "Type of energy" , "Clue ran oddly to atomic" .)