In a bowl, combine the chicken breasts with the chipotle ranch seasoning and olive oil. Ensure the chicken is well-coated. Let it marinate for at least 30 minutes (or overnight in the fridge for more flavor).
Preheat a grill or skillet over medium-high heat. Add the marinated chicken and cook for about 5-7 minutes per side, or until the internal temperature reaches 165°F (75°C). Once cooked, let it rest for a few minutes before slicing into thin strips.
In a large mixing bowl, combine the cooked brown rice, black beans, corn, diced tomato, and half of the shredded cheese. Mix well.
Lay a tortilla flat on a clean surface. In the center, layer a portion of the rice and bean mixture, followed by sliced chicken, avocado, a dollop of sour cream, and a sprinkle of the remaining cheese.
Fold in the sides of the tortilla and then carefully roll it from the bottom up to form a burrito. Ensure all fillings are tucked in well.
For an added crunch, place the wrapped burrito seam-side down in a skillet over medium heat. Cook for about 2-3 minutes on each side until golden brown and slightly crispy.
Slice the burrito in half and plate it. Garnish with fresh cilantro and serve with lime wedges on the side.
Notes
Let the chicken marinate overnight for best flavor.