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

Here is Why You Need An Adapter

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

Comoros

In Comoros, outlets of type C and E are in use.

Type C

Type E

Niue

In Niue, outlets of type I are in use.

Type I