Place poblano chiles and tomatoes (if using fresh) on a baking sheet covered with aluminum foil. Place under the broiler and char for 8 to 10 minutes, flipping a couple times in between, until charred, soft, and wrinkled.
Remove the poblanos and tomatoes from the oven. Place the poblanos in a plastic bag, close the bag, and set aside to allow the poblanos to steam and sweat for at least 10 minutes, and up to 2 hours. Remove the poblanos from the bag and in a bowl of water, or under a gentle stream of running water, peel away the charred skin. Next, cut a slit down the side of each poblano and remove the seeds and stems before cutting into strips of about 1” x 1/4”. Set aside.
Chop the broiled tomatoes into 1/2" pieces. If using canned tomatoes, simply chop them.
In a large skillet, heat the vegetable oil over medium heat. Once hot, add the onion and cook until soft and translucent, about 5 minutes. Add the garlic and cook until fragrant, a minute or two longer.
Add the chopped tomatoes (including the skins, seeds, and juices), cumin, crushed tops of the whole cloves, and salt. Cook for 3 to 4 minutes, until the mixture is dark red and thickened. Add poblanos, olives, capers, pickled jalapeños and chicken, stirring to combine. Cook for 5 more minutes.