You Do Need power plug adapter while traveling from Liechtenstein to Nepal.

Here is Why You Need An Adapter

The outlet and plug type used in Nepal are C, D and M and in Liechtenstein are C and J. This is how they look like.

Liechtenstein

In Liechtenstein, outlets of type C and J are in use.

Type C

Type J

Nepal

In Nepal, outlets of type C, D and M are in use.

Type C

Type D

Type M