You might be going off axis and nose diving because you're trying to rotate too early (the tail of the board will get hung up on the wake).
Make sure you are at the highest point of your pop before looking over your shoulder to start the rotation and passing the handle. It could help to think about initiating the rotation with your hips too, not just your shoulders.
Also, if you try to pass the handle to early, it will make it difficult to execute because the handle won't be in the correct position to be grabbed. Most likely it will be getting pulled away from your hip so make sure to wait (pop - pull - pass)
One last thing, as stated above in the other posts, if there's a lot of tension (load) on the lone when you leave the wake, that can make it very difficult to handle pass. Right before you leave the wake, try letting the handle out just a little bit and then when you're at the top of the pop, tug on the handle. This should allow you to advance your body to the boat making it easier to pass the handle.