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' is the 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" .)