Prepare the Cowboy Butter: In a medium bowl, combine the softened butter, minced garlic, parsley, chives, smoked paprika, garlic powder, red pepper flakes, salt, and pepper. Mix thoroughly until evenly combined. Set aside at room temperature to allow flavors to meld.
Cook the Linguine: Bring a large pot of salted water to a boil. Add linguine and cook according to package directions until al dente. Important: Before draining, reserve 1 cup of the starchy pasta water. Drain the pasta and set aside.
Sear the Chicken: While the pasta cooks, heat olive oil in a large skillet or pan over medium-high heat. Season the chicken pieces with salt and pepper. Add to the hot skillet in a single layer and sear for 3-4 minutes per side, until golden brown and cooked through (165°F / 74°C). Remove the chicken from the skillet and set aside.
Make the Sauce: To the same skillet, add the white wine (or chicken broth) to deglaze, scraping up any browned bits from the bottom. Let it simmer and reduce by half, about 2-3 minutes. Add half of the prepared Cowboy Butter and stir until melted and fragrant.
Combine and Finish: Return the cooked chicken to the skillet, then add the drained linguine. Toss to combine, adding the remaining Cowboy Butter and the optional heavy cream. If the sauce is too thick, stir in a splash of the reserved pasta water until it reaches a silky consistency.
Serve: Remove from heat and stir in the Parmesan cheese. Transfer to serving bowls, garnish with extra fresh parsley, and serve immediately with lemon wedges on the side for squeezing.