In a large skillet over medium heat, add a drizzle of olive oil. Once hot, add the chopped onion and diced bell pepper. Sauté until softened, about 5 minutes.
Add the minced garlic to the skillet and cook for an additional minute, just until fragrant.
Stir in the ground chicken; cook until browned and fully cooked through, about 7 to 10 minutes.
Season the chicken mixture with chili powder, cumin, paprika, salt, and pepper.
Add the cooked brown rice, black beans, and corn to the skillet. Mix well and cook for another 2-3 minutes, allowing the flavors to meld together.
Remove from heat and stir in the shredded cheese until it melts slightly.
Lay out a tortilla on a flat surface and spoon a generous amount of the ground chicken mixture onto the center. Fold in the sides, then roll tightly from the bottom up to form a burrito.
Repeat with the remaining tortillas and filling.
Optional: You can grill the burritos on a skillet with a bit of oil to achieve a crispy exterior and enhance the flavor for about 2 minutes on each side.
Slice each burrito in half and serve with avocado slices, fresh cilantro, and your choice of salsa or hot sauce.