A looser nock fit, as long as the nocks aren't falling off the string, is a good thing, so let's ignore that for the moment.
Left hits can result from tuning or strike plate material. If you're satisfied that your bow and arrows are in tune, you could try using a softer strike plate material, like a rug rest, and see if that moves the POI over a few inches.
Form issues that might result in left hits include not getting your eye over the arrow, not getting your elbow back behind the arrow, not pointing your bow arm shoulder at the target, and torquing the string or bow. Unlocking your bow arm, bending it slightly, might also help.