Place the chicken on one half of a piece of parchment paper. Fold the parchment over and with a meat mallet, pound the chicken to ½ inch thickness.
Mix the onion powder, garlic powder, paprika, salt, and pepper together in a small bowl. Sprinkle evenly over both sides of the chicken.
Heat a cast-iron skillet over medium heat. Add the oil and the chicken to the pan. Cook until brown, approx 2-3 minutes. Flip and brown the other side for another 2-3 minutes.
Transfer the skillet to the oven and bake for 5 minutes until the internal temperature is 165 degrees. (Note 2) Top each chicken breast with a slice of cheese. Remove the skillet from the oven and rest the chicken while you assemble the sandwiches. (The residual heat is enough to melt the cheese.)
Spread the top and bottom buns with the barbecue sauce. Top each bottom bun with half of the pickles. Place a piece of chicken on top of the pickles. Top the chicken with the bacon, two slices per sandwich. Replace the top bun and serve.
For larger, thicker chicken breasts, slice the chicken in half horizontally and pound as necessary to achieve an even thickness. One large piece of chicken will make two sandwiches.
This cooking method keeps the chicken moist and tender. During warmer months, you can also cook the chicken on the grill.