Melt the butter in a large skillet over medium-high heat. Add the chicken strips seasoned with sea salt and ground pepper. Cook until golden brown and cooked through, about 5 to 7 minutes.
Add the diced onion and garlic to the skillet. Sauté until soft and fragrant, about 3 minutes.
Pour in the chicken stock and roasted red peppers. Stir and let simmer for about 2 minutes.
Add the heavy cream and shredded parmesan cheese along with Italian seasoning. Stir until combined and let simmer until thickened, about 3–4 minutes.
Toss in the drained pepperoncini peppers and stir just long enough to warm through, about 1 minute.
Serve over rice or pasta, or enjoy straight from the pan. Garnish with extra parmesan cheese if desired.