Cook the linguine according to package instructions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium-high heat. Add the chicken pieces, garlic powder, onion powder, smoked paprika, salt, and black pepper. Cook for about 5-7 minutes, stirring occasionally, until the chicken is cooked through and golden brown.
Reduce the heat to low and pour the melted butter over the chicken. Stir in the chopped parsley, lemon juice, and red pepper flakes if using.
Add the cooked linguine to the skillet and toss everything together until the pasta is well coated with the buttery sauce.
Serve immediately, topped with grated Parmesan cheese.