In a large bowl, whisk together olive oil, lime juice, chili powder, cumin, smoked paprika, garlic powder, onion powder, salt, and pepper. Add the chicken breasts and toss to coat evenly. Cover the bowl and refrigerate for at least 30 minutes, or up to 2 hours for best flavor. If short on time, 15 minutes at room temperature is acceptable.

While the chicken marinates, combine rice, water (or broth), and salt in a medium saucepan. Bring to a boil, then reduce heat to low, cover, and simmer for 15-18 minutes, or until all water is absorbed. Remove from heat and let stand, covered, for 5 minutes. Fluff with a fork, then stir in fresh lime juice and chopped cilantro. Keep warm.

Rinse and drain the black beans. If using canned corn, drain it. If using frozen corn, thaw it. Dice the avocado. Prepare any other desired toppings (e.g., chop fresh tomatoes, red onion, jalapeño if using).

Preheat a grill or grill pan to medium-high heat. Lightly oil the grates. Place marinated chicken breasts on the hot grill. Cook for 6-8 minutes per side, or until internal temperature reaches 165°F (74°C) and chicken is cooked through with nice grill marks. Remove chicken from the grill and let it rest on a cutting board for 5 minutes before slicing or dicing.

While the chicken rests, in a small saucepan or microwave-safe bowl, gently warm the rinsed black beans and drained corn kernels over low heat or in the microwave until heated through.

Divide the cilantro-lime rice among 4 bowls. Top each serving of rice with sliced or diced grilled chicken, warm black beans, warm corn, diced avocado, a dollop of salsa, and optional sour cream/Greek yogurt and cotija cheese. Serve immediately with fresh lime wedges.