Oil temperature is everything (solid Crisco-end of story).
1) Bring the temperature up slowly versus cranking to high. That way the skillet will get just the right amount of heat and you won’t have to drop the temp when it keeps shooting past where you want it. You would think the chicken would help cool the oil but it doesn’t. So if you heat it up fast the temp will keep rising and the chicken will cook too fast at first, then too slow.
2) make the depth of the oil between halfway and 3/4ths up the chicken after you have filled the skillet. You want to cook on both sides once instead of all the way in the oil.
3) This is how you get the temp right-assuming you are heating the oil real slow, the temp is right when you see the VERY FIRST wisps, just hints, of smoke. If it is smoking solid, its too hot.
Another trial and error way to tell, the chicken should be bubbling all around the edges, but very little. When you get the right temp it really looks like you are cooking too slow, but you are not! If a regular chicken thigh can’t go a full 15 minutes on each side without getting too brown or even burned, you are cooking too fast. If the bubbles aren’t coming up all the way around a piece, then you are too slow. Cover the skillet for a couple of minutes to bring the temp up a bit before you turn up the fire, you want to change the temp slowly.