You Do Need power plug adapter while traveling from Niue to Turks and Caicos Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Turks and Caicos Islands are A and B and in Niue is I. This is how they look like.

Niue

In Niue, outlets of type I are in use.

Type I

Turks and Caicos Islands

In Turks and Caicos Islands, outlets of type A and B are in use.

Type A

Type B