Chop chicken into bite-size pieces (about ½-inch); heat a skillet with 1 tbsp oil over med-high, cook undisturbed 3 min until starting to brown, flip + sauté 3-5 min more until fully cooked + no pink remains; save half the chicken for later

Meanwhile, stack 4 tortillas on a plate + wrap with a damp paper towel; microwave 15-30 sec or until warm + soft

Wash + thinly slice 1 head of lettuce; add meat + lettuce to tortillas

Dollop each with 1 tbsp sour cream + sprinkle on 1 tbsp cheese