Relative having base in Riviera location (5)
I believe the answer is:
niece
'relative' is the definition.
(type of relative)
'base in riviera location' is the wordplay.
I cannot quite see how this works, but
'base' could be 'e' (mathematical symbol) and 'e' is present in the answer.
The remaining letters 'nice' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'having' acts as a link.
Can you help me to learn more?
(Other definitions for niece that I've seen before include "[PRIEST'S] daughter?" , "A sibling's daughter" , "Young female relative" , "Family relative" , "Female relation" .)