Cut the chicken breast into small, bite-sized pieces and season with sea salt, black pepper, cumin, and garlic powder.
Heat the olive oil in a skillet over medium-high heat. Add the chicken and sauté until golden brown and cooked through, about 6-8 minutes.
While the chicken cooks, rinse and drain the black beans. Warm the beans and the pre-cooked white rice in a small saucepan or microwave until heated through.
Warm the flour tortilla in a dry skillet for 30 seconds on each side until soft and pliable.
Lay the tortilla flat and spread the sour cream and guacamole down the center.
Layer the cooked rice, black beans, sautéed chicken, and shredded romaine lettuce over the spreads.
Fold the sides of the tortilla inward, then roll tightly from the bottom to create a secure burrito.
Slice the burrito in half diagonally and serve immediately.