Heat vegetable oil in a large skillet over medium-high heat.
Add diced chicken and cook, stirring occasionally, until no longer pink, about 5–7 minutes.
Stir in chili powder, ground cumin, garlic powder, onion powder, salt, and black pepper; cook 1–2 minutes more, until fragrant and chicken reaches 165°F. Remove chicken and set aside.
In a medium saucepan, combine uncooked long-grain white rice and water; bring to a rolling boil.
Reduce heat to low, cover, and simmer 15–18 minutes, until water is absorbed and rice is tender; fluff with a fork.
Rinse and drain black beans; warm in a small saucepan or microwave if desired.
Lay a flour tortilla flat and layer ¼ cup cooked rice, ¼ cup seasoned chicken, a spoonful of black beans, a dollop of salsa, and a sprinkle of shredded cheese down the center.
Fold in tortilla sides, then the bottom edge over the filling, and roll up tightly.
(Optional) Heat a clean skillet over medium heat and place burritos seam-side down; cook 2–3 minutes per side until golden and crispy.
Serve immediately with optional sour cream, chopped fresh cilantro, lime wedges, or guacamole.