Prep the marinade: In a large bowl, whisk olive oil, lime juice, minced garlic, chili powder, cumin, smoked paprika, oregano, garlic powder, cayenne (if using), salt, and black pepper.
Slice the chicken: Cut into thin strips for fast, even cooking. Add to the marinade and toss to coat. Marinate for at least 20 minutes or up to 8 hours in the fridge.
Slice the veggies: Cut bell peppers and onion into 1/2-inch strips.
Pat them dry so they char instead of steam.
Cook the chicken: Heat a large skillet over medium-high. Add a little oil. Cook the chicken in batches 4–6 minutes, stirring occasionally, until browned and cooked through.
Transfer to a plate and tent with foil.
Cook the peppers and onions: In the same skillet, add a touch more oil if needed. Sauté peppers and onions 6–8 minutes until tender-crisp with some char. Season with a pinch of salt and pepper.
Warm the beans and corn: In a small saucepan, heat black beans and corn with a splash of water and a pinch of salt until warm.
Drain excess liquid if needed.
Prepare the base: Fluff cooked rice (or warm cauliflower rice). Squeeze in a bit of lime and sprinkle chopped cilantro if you like.
Assemble: In bowls, add rice, then top with chicken, peppers and onions, black beans, and corn. Add avocado, a dollop of Greek yogurt, salsa, cilantro, and jalapeños.
Sprinkle cheese if using.
Taste and finish: Squeeze fresh lime over the top. Adjust salt or heat to your preference.