Preheat oven to 425°F. Line a large sheet pan with foil.
Trim and pat dry the chicken. In a large bowl, whisk together 2 tsp chili powder, 1 tsp cumin, 1 tsp garlic powder, 1 tsp paprika, 1/2 tsp ground coriander, 2 tsp salt, 1-1/2 tsp pepper, 2 tbsp + 2 tsp olive oil, and 4 tsp balsamic vinegar. Add the chicken and toss with a spatula until well-coated. Place chicken flat (not bunched up), smooth side up, on prepared sheet pan, leaving space between pieces.
Bake for 15 minutes. Remove the pan and move the oven rack about 8 inches from the broiler. Switch oven to broil (no need to wait for it to heat) and place the tray back in the oven. Broil for 7–9 minutes or until chicken is nicely blackened and caramelized. Let rest for 10 minutes, then slice into strips or cubes. Squeeze fresh lime on top, if desired. Discard foil from pan.
Switch heat to 500°F. Add the sliced peppers and onions to the same bowl used for the chicken. Add 1-1/2 tsp chili powder, 1/2 tsp paprika, 1/2 tsp garlic powder, 1/2 tsp onion powder, 1/2 tsp salt, 1/4 tsp pepper, and the remaining 2 tbsp olive oil. Toss with a spatula until well coated. Add to the same sheet pan and spread out evenly. Broil for 1–2 minutes, watching closely.
Serve hot with warm tortillas and your favorite toppings.
Video
Notes
Note 1: Use about 6–7 evenly sized chicken thighs. Chicken breasts won’t work well with this method, but here’s how to use them: Pound to about 1/2 inch thick using a rolling pin, meat mallet, or your fist so the pieces cook evenly (or cut thick breasts in half widthwise). Toss with oil, spices, and vinegar, then bake at 425°F for 18 minutes or until golden and cooked through.Note 2: Great toppings include avocado, sour cream, Mexican crema, cheese, lime, and cilantro.To Warm Tortillas: Microwave wrapped in a damp paper towel for 20–30 seconds or toast in a dry skillet for 30 seconds per side. For charred tortillas, spray lightly with cooking spray, then use tongs to hold over a low gas flame for a few seconds per side until lightly charred.Storage: Store chicken, veggies, and toppings separately in airtight containers in the fridge for up to 4 days. Reheat chicken and veggies in a skillet over medium heat or in the microwave until warmed through.