Heat 1 Tbsp olive oil in your pot over medium-high heat. Add diced chicken and sprinkle fajita seasoning over it. Cook 6–8 minutes until golden and cooked through, then remove from the pot and keep warm.
In the same pot, add remaining olive oil and butter. Add onion, red pepper and green pepper. Cook 3–4 minutes until softened. Add garlic and cook for 30 seconds until fragrant.
Add tomatoes, black beans, chili powder, cumin, paprika, coriander and chicken broth. Stir well, scraping the bottom of the pot. Add rice, bring to a boil, then cover and simmer for 20–23 minutes until rice is tender.
Fluff rice with a fork. Stir in 1 cup cheese, cilantro, lime juice, corn and the cooked chicken. Top with remaining cheese, cover and let it melt before serving.