How to Make It
Stir together ketchup, chipotles, paprika, cumin, 1/2 cup of the cola, and 1 teaspoon of the salt in a small saucepan over medium-high. Cook, stirring often, until slightly thickened, about 10 minutes. Stir in vinegar, and remove from heat.
Stir together garlic powder, black pepper, and remaining 1 1/2 teaspoons salt in a small bowl. Pat chicken pieces dry, and season evenly with spice mixture. Line a rimmed baking sheet with aluminum foil, coat with cooking spray, and set aside.
Place water and remaining 1/2 cup cola soft drink in a programmable pressure multicooker (such as Instant Pot). (Times, instructions, and settings may vary according to cooker brand or model.) Add chicken. Pour 1/2 cup of the barbecue sauce over chicken, but do not stir.
Preheat oven to broil with oven rack 6 inches from heat. Cover cooker with lid, and lock in place. Turn steam release handle to SEALING position. Select MANUAL/PRESSURE COOK setting. Select HIGH pressure for 10 minutes. (It will take 10 to 15 minutes for cooker to come up to pressure before cooking begins.) When cooking has stopped, carefully turn steam release handle to VENTING position, and let steam fully escape (float valve will drop). (This will take 3 to 4 minutes.) Remove lid from cooker. Carefully remove chicken pieces, and place in a single layer on prepared baking sheet. Discard cooking liquid.
Spoon remaining barbecue sauce evenly over chicken. Broil in preheated oven until sauce is lightly browned and skin is slightly crispy, 5 to 7 minutes. Serve immediately.