Season the chicken all over with salt, pepper, and 1/4 tsp. garlic powder. Let the seasoned chicken rest at room temperature while you prepare the other ingredients.
Thinly slice the bell peppers and onions. Set aside.
Heat one tablespoon of oil in a large skillet over medium heat. Cook the chicken for 3-4 minutes per side (until cooked through). Transfer the chicken to a cutting board and tent with foil.
Add the remaining oil to the skillet. Add the bell peppers, onions, remaining garlic powder, Italian seasoning, and a pinch each of salt and pepper. Turn the heat up to medium-high.
Cook the vegetables until tender and slightly charred, about 6-8 minutes. Turn the heat down to medium
Thinly slice the chicken into strips. Stir the chicken into the pan with the vegetables.
Divide the chicken and vegetable mixture into two separate piles in the pan (preferably in a shape resembling the bread you are using.) Cover each pile with provolone cheese, and let the cheese melt over the tops of the piles.
Warm the sausage rolls in the microwave for about 20 seconds.
Scoop one of the chicken and vegetable piles into a warm sausage roll. Repeat with remaining sausage roll. Serve hot!