In a bowl whisk together chipotle peppers, buttermilk, egg, cornstarch, salt and pepper.
Cut the chicken breasts into 1 inch pieces. Place the chicken in the batter and let it sit for at least a couple hours in the fridge or overnight.
Pour some panko breadcrumbs in a shallow plate.
Heat the oil in a large skillet.
Coat each piece of chicken with breadcrumbs, add more breadcrumbs as needed and fry on both sides for 3 to 5 minutes until chicken is cooked through. Place on paper napkins to soak up some of the oil. Repeat with all chicken pieces. Only add a few pieces of chicken to the skillet at a time so as not to over crowd, so the chicken turns out crispy.
Once out of fryer, season with more salt, pepper (if desired) and chopped cilantro to taste.