Preheat grill to medium heat; grease grates well.
In medium bowl, toss chicken with oil and taco seasoning until coated.
Grill chicken, turning once, for 10 to 12 minutes or until chicken is cooked through and instant-read thermometer registers 165°F when inserted into thickest part of chicken. Let rest for 5 minutes. Using 2 forks or your fingers, shred chicken. Toss with 2 tbsp lime juice.
Warm chalupas in pan according to package directions.
In small bowl, stir together sour cream, chipotle peppers, adobo sauce and remaining lime juice until combined.
Divide chicken mixture among chalupas and top with sour cream mixture, lettuce, pico de gallo and cheese. Serve with lime wedges.
To promote even grilling, pound chicken with meat mallet to even thickness between 2 sheets of plastic wrap. For a variation, substitute taco seasoning with tajin seasoning to taste.