Preheat oven to 425℉. Butterfly chicken and season with salt and pepper. Brush with ¼ cup chipotle BBQ sauce and marinate for up to 2 hours.
In a medium bowl, combine all pico de gallo ingredients and place in the fridge covered.
Add corn to the baking sheet. mix with 1 tablespoon olive oil and season with salt and pepper. Roast in the oven for 15-20 minutes.
Preheat the grill to medium. Place chicken on the grill for 5 minutes per side. Before flipping, brush the chicken with another ¼ cup of chipotle BBQ sauce, then flip and brush again with more sauce. Cook until the temperature reaches 160℉, about 8-10 minutes total. Set aside to rest.
Clean and chop romaine lettuce. Combine with cilantro lime ranch dressing and separate onto 4 plates. Top with pico de gallo, corn, cheese, and avocado. Slice chicken into strips and toss with the remaining ¼ cup of chipotle BBQ sauce. Add chicken to the salad and serve.
Only combine the lettuce with ranch and top it with the rest of the ingredients. This will ensure it doesn't get watered down by the pico de gallo before it gets mixed with the rest of the ingredients.
When grilling BBQ chipotle chicken, the key to getting the sauce to stick to the chicken is brushing it on again while the chicken is grilling. Cooking the chicken at a medium temperature lets the sugar caramelize on the chicken and stick. I also suggest tossing in BBQ sauce again.