Preheat your grill or grill pan over medium-high heat. In a small bowl, mix together the chili powder, garlic powder, onion powder, cumin, salt, and black pepper. Rub the spice mixture evenly over the chicken breasts.
Drizzle olive oil on the grill and place the seasoned chicken breasts on it. Grill for about 6-7 minutes per side, or until the internal temperature reaches 165°F. Remove from the grill and let rest for 5 minutes before slicing.
While the chicken is resting, warm the flour tortillas in a dry skillet over medium heat for about 30 seconds on each side until pliable.
To assemble the burritos, place 1/2 cup of cooked rice in the center of each tortilla. Top with sliced grilled chicken, a drizzle of chipotle ranch dressing, shredded lettuce, diced tomatoes, and shredded cheddar cheese.
Fold in the sides of the tortilla and then roll it up tightly from the bottom. Repeat with the remaining tortillas and ingredients.
Serve immediately, or wrap in foil and keep warm in a low oven until ready to serve.