2 T. coconut oil (or olive, or vegetable, if you must)
1 tsp. salt
2 T. apple cider vinegar
1/4 c. brown sugar
fresh cilantro to taste (optional)
Mix all ingredients, pour over chicken and simmer until chicken is cooked.
You may want to taste it beforehand. "You want it tart enough that your jaw tingles a bit but not so much that you get a sustained pucker. A lot of the tartness goes away with cooking so a bit of a bite is good"
"I would cook the peppers and onions separately from the chicken. Maybe caramalize the onions a bit"
"If you [marinade the chicken] make sure the marinade is strong. The citrus and vinegar help break the meat down but the water in the chicken dilutes it. I usually just cut up the chicken and throw it in the skillet pour the sauce on and cook. You don't want the chicken to be swimming. If possible you want the sauce to cook down and maybe even caramelize a bit on the chicken. That balance is really hard to get just right though. I would prefer a bit too much sauce to not quite enough."
This is enough sauce for 3-4 large chicken breasts cut into small chunks. Perhaps more.
This sauce is also good with chicken and shrimp.
If you don't like spicy sauces, leave out the cayenne and red pepper. You'll get a nice sweet seasoning.