Preheat oven to 375°F. Heat vegetable oil in a large skillet over medium heat. Add chicken thighs and cook until browned and fully cooked, about 6-8 minutes per side. Transfer to a plate and shred with two forks.
In the same skillet, sauté onion and garlic until softened, about 3 minutes. Stir in mole sauce and chicken broth, simmering for 5 minutes until smooth and slightly thickened. Remove from heat and mix in shredded chicken.
Warm tortillas in a dry skillet or microwave wrapped in a damp towel for 30 seconds to make them pliable. Spread 1/2 cup mole sauce on the bottom of a baking dish.
Fill each tortilla with 1/4 cup chicken mixture, roll tightly, and place seam-side down in the dish. Pour remaining mole sauce over the top and sprinkle with Oaxaca cheese.
Bake uncovered for 20 minutes until cheese is melted and bubbly. Garnish with queso fresco, cilantro, and sesame seeds before serving.