Prep the chicken: Pat chicken dry and slice thinly against the grain. Toss with smoked paprika, onion powder, garlic powder, oregano, salt, and pepper.
Heat the pan: Set a large skillet over medium-high heat.
Add 1 tablespoon oil.
Cook the veggies: Add onions and peppers with a pinch of salt. Sauté 6–8 minutes until softened and lightly caramelized. Add mushrooms and cook 3–4 minutes more.
Transfer veggies to a plate.
Sear the chicken: Add remaining oil. Spread chicken in a single layer and cook 3–4 minutes per side until browned and cooked through.
Build flavor: Add garlic and Worcestershire. Stir 30 seconds until fragrant.
Return veggies to the pan and toss to combine.
Add the cheese: Lower heat to medium-low. If using cream cheese, stir it in now for a silky sauce. Lay provolone slices over the mixture or sprinkle shredded cheese.
Cover for 1–2 minutes until melted.
Assemble bowls: Spoon over warm cauliflower rice or cabbage, or enjoy as-is. Garnish with chopped parsley and black pepper.
Taste and finish: Adjust salt, add a splash more Worcestershire if needed, and serve hot.