Heat a large skillet over medium heat. Add a drizzle of oil, then sauté the diced onion, green pepper, and mushrooms for 4–5 minutes, until softened and fragrant. Add the minced garlic and cook another 30 seconds.

Add the ground chicken to the skillet. Break it apart with a spatula as it cooks. Stir in Italian seasoning, smoked paprika, salt, and pepper. Continue cooking until the chicken is fully browned and no pink remains (about 6–8 minutes).

Slice the buns in halves. Add two mozzarella slices in each bun. Spoon the chicken and veggie mixture evenly onto the sandwich buns.

Place the assembled sandwiches open-faced on a baking sheet and broil for 1–2 minutes, just until the cheese is melted and bubbly and the buns are lightly toasted. Watch closely to prevent burning

Serve warm and enjoy!