a nutcracker is a second class lever

Deciding what lever a nutcracker is a difficult one, but it is definitely a second class lever. 

Why? Before the nut touches the top handle you lift the nut upwards by applying a force one end and the other end is a fulcrum (pivot point). A second class lever has the load in the middle (e.g. a wheelbarrow):

But with a nutcracker you just happen to put a ceiling in the way.

As it hits the ceiling (the top handle) the load just happens to increase until the nut cracks.

The confusion occurs because the ceiling (the top handle) happens to attach to the fulcrum (pivot point).