You Do Need power plug adapter while traveling from Nigeria to Rwanda.

Here is Why You Need An Adapter

The outlet and plug type used in Rwanda are C, E, F and G and in Nigeria are D and G. This is how they look like.

Nigeria

In Nigeria, outlets of type D and G are in use.

Type D

Type G

Rwanda

In Rwanda, outlets of type C, E, F and G are in use.

Type C

Type E

Type F

Type G