Why did my homemade chicken strips burn?!

you got the oil too hot, even if the temp was on medium!! and you left them too long before turning.

Use a bread cube to test the temperature of the oil iin skillet. It should brown in about 15 seconds for medium temperature.
I use a drop of water and it should dance on the oil for about 15 seconds or maybe a bit less.

getting the oil too cool will cause the batter to take up too much oil.

The most common sense answer would be that you had your oil too hot.
You cannot set a burner to "medium' and assume that is the temp it will be(what exactly would "medium" be??)
At the first sign of getting dark too fast, you could have removed the pan from the burner to allow it to cool down and turn down the burner.
That is partly the problem with blindly following a recipe. All recipes assume the cook has basic knowledge.
And....this is a great learning experience. any mistake in cooking is. You can bet you won't repeat it again.
Finding out what went wrong is the first step in learning.
Anyone who has ever cooked for ANY length of time has made a goofy mistake.

Chibi: I am a retired Diplomat from the State Dept Diplomatic Corp..have served at Embassies all over the planet which means we have to learn to do everything ourselves because we have to entertain and there are no Walmart's, Pizza Hut's etc. Now retired, and I have a full kitchen, poolside where I do all my cooking and I still prepare flaming dishes etc..All that to tell you why I know these things.

Now..the answer to your question. The bottom line is that in any type cooking, baking, frying, whatever, there is a scientific answer to your question. Pizza, for example (I've watched this in Italy in the brick ovens where the pizza is placed directly on the bricks beside the burning wood fire), is properly baked at 700 degrees. This explains why it's difficult to bake pizza at home because home ovens only go to 500. The reason for 700 is because the pizza is very thin. That's the answer..your heat was too hot for the thickness of your Chicken Strips.

Think of it this way. I'll use the oven to illustrate (But its the same for frying also). To bake a cake, you must use a low heat because the cake is thick. You use a slow heat to allow it to reach all the way to the center of the cake before the outside burns. The pizza is thin, so you should bake it hot and fast.

The test..Whatever it is you baked..if it was too dry in the center..your heat was too low. If it's still wet and doughy in the center, your heat was too hot. There is a temp for which the center and the outside will both be done at the same time/Juan

The oil was too hot. It's best to use a frying thermometer in frying oil to ensure proper temperature

Oil is to hot

your oil was too hot