Cook your base. Prepare brown rice or quinoa according to package directions.
For cauliflower rice, sauté in a dry skillet over medium heat for 5–7 minutes until just tender. Set aside.
Season the chicken. Pat chicken dry and sprinkle with salt, pepper, chili powder, cumin, and smoked paprika. Rub in the spices so the surface is evenly coated.
Sear and cook the chicken. Heat 1 tablespoon oil in a large skillet over medium-high.
Add chicken and cook 4–6 minutes per side until browned and cooked through (165°F). Transfer to a cutting board to rest, then slice or shred.
Build the veggie base. In the same skillet, add a drizzle more oil if needed. Sauté onion and bell peppers with a pinch of salt for 4–5 minutes until softened.
Stir in garlic for 30 seconds.
Add beans, corn, and tomatoes. Pour in black beans, corn, and fire-roasted tomatoes. Sprinkle in oregano and a pinch of cayenne if using. Stir and cook 2–3 minutes to warm through.
Whisk up the sauce. In a small bowl, whisk broth, tomato paste, and vinegar.
Bring the veggie mixture to a gentle simmer, then stir in the cornstarch slurry. Cook 1–2 minutes until slightly thickened and glossy.
Combine with chicken. Add the sliced or shredded chicken back to the skillet. Toss to coat in the sauce and simmer 1 minute.
Taste and adjust salt, pepper, or lime if you like brightness.
Assemble the bowls. Spoon rice or cauliflower rice into bowls. Top with a generous scoop of the chicken and veggie mixture.
Finish with fresh toppings. Add avocado, cilantro, a dollop of Greek yogurt, a sprinkle of cheese if using, and lime wedges. Jalapeños for heat, or shredded lettuce for crunch.