You may be correct in your diagnosis, but if so, the root cause is probably a step back from that. If you are drawing the bow with your back muscles, such that your forearm and hand are relaxed, except for the hook in your fingers, and if you're holding the bow with a loose enough grip that the bow handle can move to align itself with the forces acting on it, then the bow and arrow will naturally align themselves with the force of your string hand pulling back and your bow hand pushing forward. There should be no forces acting in any direction other than straight back and straight forwards, which should eliminate problems like your index finger pushing down on the nock automatically, and a lot of other problems that could otherwise be difficult to identify.