Cook the chicken in olive oil until no longer pink.
Shred the cooked chicken and mix in ranch dressing.
Prepare your toppings: dice the avocado, shred the lettuce, and chop the tomatoes.
Warm the flour tortillas in a skillet until pliable.
Assemble the burritos by layering the filling and toppings in each tortilla.
Roll the tortillas tightly, tucking in the sides as you go.
Toast the assembled burritos in a skillet until golden brown on both sides.
Slice the burritos in half and serve with extra ranch dressing.