You can read the transform of the character’s hand sockets in your nunchaku abp (maybe by accessing the attached component and casting to skeletal mesh, or somehow passing the character’s component to the anim instance). I think sadly this has to be run on update (on the game thread)
You can then use the Transform Bone node to set the location of the nunchaku bones to that of the hands
Otherwise, if the names of the bones are the same, you can use the CopyPoseFromMesh node, which will copy the transforms of bones from the by default attached or otherwise provided source mesh to those of the same name of this skeletal mesh