The node to add angular momentum to a rigid body is ‘Add Torque’. The node needs a vector as input. The direction of the vector is the axis of rotation and the length is the force you want to apply.
You probably need to modify the maximum angular velocity attribute of the rigid body as well to get a fast spinning body.
If Unreal’s physics system conserves the angular momentum, which would prevent the object from falling over, I do not know.