You Do Need power plug adapter while traveling from Andorra to Niue.

Here is Why You Need An Adapter

The outlet and plug type used in Niue is I and in Andorra are C and F. This is how they look like.

Andorra

In Andorra, outlets of type C and F are in use.

Type C

Type F

Niue

In Niue, outlets of type I are in use.

Type I