Prep the chicken and veggies. Dice the chicken into small, bite-size pieces for fast, even cooking.
Chop the onion and bell pepper, and mince the garlic.
Heat the pan. Set a large skillet over medium-high heat and add the oil. When it shimmers, add the chicken in a single layer. Season lightly with salt and pepper.
Brown the chicken. Cook 4–6 minutes, stirring a couple of times, until the edges are golden and the chicken is mostly cooked through.
Transfer to a plate and keep warm.
Soften the vegetables. In the same skillet, add the onion and bell pepper. If the pan looks dry, add a splash more oil. Cook 3–4 minutes until softened, then stir in the garlic for 30 seconds.
Bloom the spices. Add chili powder, cumin, smoked paprika, garlic powder, onion powder, oregano, red pepper or cayenne (if using), and a pinch of salt.
Stir for 30–45 seconds to release aroma.
Build the sauce. Stir in the tomato paste, then add diced tomatoes with their juices and the chicken broth. Scrape up any browned bits from the bottom of the pan for extra flavor.
Add beans and corn. Stir in the black beans and corn. Bring to a gentle simmer.
Return the chicken. Add the browned chicken and any juices back to the skillet.
Stir, reduce heat to medium, and simmer 4–6 minutes until the chicken is cooked through and the sauce slightly thickens.
Finish with lime and cilantro. Squeeze in the juice of half a lime and stir in chopped cilantro. Taste and adjust salt, pepper, or heat as needed. If using cheese, sprinkle it over the top and let it melt for 1–2 minutes.
Serve your way. Spoon over rice or cauliflower rice, tuck into tortillas, or serve bowl-style with shredded lettuce, avocado, salsa, and a dollop of Greek yogurt.