01 - Set oven temperature to 400°F to prepare for toasting rolls and melting cheese.
02 - Heat 1 tbsp olive oil in a large skillet over medium heat. Add sliced onion and bell peppers. Cook for 8–10 minutes, stirring occasionally, until softened and lightly caramelized. Remove vegetables from skillet and set aside on a plate.
03 - Add remaining 1 tbsp olive oil to the same skillet. Place sliced chicken in the pan and sprinkle with salt, black pepper, garlic powder, and paprika. Cook for 6–8 minutes, stirring occasionally, until chicken is cooked through and lightly browned.
04 - Return the sautéed vegetables to the skillet with the cooked chicken. Stir everything together and cook for an additional 2 minutes to heat through and blend flavors.
05 - Slice each hoagie roll lengthwise, keeping one edge attached like a hinge. Spread softened butter on the cut sides. Arrange rolls butter-side up on a baking sheet and toast in the preheated oven for 3–4 minutes until lightly golden.
06 - Distribute the chicken and vegetable mixture evenly among the toasted rolls. Place 2 slices of provolone cheese on top of each sandwich.
07 - Return the assembled sandwiches to the oven for 3–4 minutes until the cheese is completely melted and bubbly. Serve hot.