I'd like to halve the recipe. How would you suggest I do this?

Ingredients here are easily divisible in half, and probably need less cooking time - maybe half or 2/3. Check chicje6n internal temp reaches 160-165F.
Or "cook once, eat twice." Make the whole recipe, serve half and freeze other half for a future meal.

If you have the room in your freezer, I'd make the full recipe worth of the sauce, and divide that in half. Freeze the half you don't need to use, and cook your chicken in the other half. Adobo freezes very well, and that way you'd have it on hand for a future dinner. Then you can add it to what ever sort of meat you prefer- pork or chicken, or even beef. It actually improves with time, so the second round will be even tastier. Same goes for any leftovers, by the way.