In a small bowl, mix chili powder, cumin, smoked paprika, garlic powder, onion powder, salt, and pepper.
Pat chicken dry, rub with 1 tbsp olive oil, then coat evenly with the seasoning mix. Let rest while you prep other ingredients.
Heat remaining 1 tbsp olive oil in a skillet over medium-high heat. Cook chicken 5-7 minutes per side until golden and cooked through (internal temp 165°F). Transfer to a cutting board and let rest 5 minutes before dicing.
In a small bowl, whisk together sour cream, mayonnaise, cilantro, lime juice, garlic, and salt. Refrigerate until ready.
In a large bowl, combine romaine, black beans, corn, tomatoes, radishes, and cotija. Add diced chicken and avocado. Drizzle with dressing and toss gently.
Serve with tortilla chips on top or on the side.