Hey Jacob,
I think the list of ingredients is on point.
I would add a few things ...

I would change the garlic powder to fresh garlic, minced (a lot) like an entire garlic:), and the onion powder I would change to one fresh onion and chop it finely.
If you can get scotch bonnet pepper (great, but very hot). Great flavour, but jalapeno or regular chilli would work too, and it depends on the person's palette, of course.

• Mix all those spices together (I think you could skip the sugar)

Add some liquid to the spices to create a paste, and marinate the chicken in it. (some people might blend the spices with the onion and garlic, but I like the texture, so I would just mix it thoroughly).

• Also I would double that amount of thyme, and in Jamaica, we season all our meat with chopped spring onions.

The liquids I would suggest: (with approx measurements to match the rest of your ingredients).

• wine white vinegar, or rice wine vinegar, or even balsamic vinegar, or mirin marinade (1/4 or 1/2 cup)
• add some Olive Oil (maybe 3 tbsp)
• soy sauce (3 tbsp)
• tomato sauce (3 tbsp)
• mustard (dijon, wholegrain, English, optional, 1 tbsp)
• a squeeze of lemon

Marinate the chicken in this overnight or at least 45 minutes, and then remove the chicken from the marinade (save the marinade for a gravy or gradually add the marinade while cooking the chicken).

Then it should look something more like this:

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This is just how I would improve the ingredients that you already have.

You see the wood in the photo, that's the secret to the real authentic Jamaican Jerk. It's the pimento wood...unfortunately I haven't encountered it outside of Jamaica:)

I am excited for your recipe, nice job.
This should be lip-smacking and delicious 😋