In a mixing bowl, whisk together olive oil, lime juice, minced garlic, chipotle chili powder, smoked paprika, ground cumin, salt, and black pepper. Coat the chicken thoroughly in this marinade and let it marinate in the refrigerator for at least 30 minutes.

Preheat the grill pan over medium-high heat. Place the marinated chicken onto the grill pan and sear for about 6-7 minutes on each side, until golden char marks develop and the internal temperature reaches 165°F. Let it rest for 5 minutes and then slice thinly.

In a blender, combine ranch dressing, chipotle peppers in adobo sauce, lime juice, and garlic powder. Blend until creamy and adjust seasoning with salt to taste.

Warm the tortillas on a skillet or in a microwave. Layer them with cooked rice (if used), sliced grilled chicken, tomatoes, red onion, cilantro, cheese, lettuce, avocado, and drizzle with chipotle ranch sauce. Wrap tightly.

Serve warm, sliced in half or whole on a plate. Offer extra chipotle ranch sauce on the side for dipping.