Bring a large pot of salted water to a boil. Add the noodles and cook according to the package directions, 5 to 6 minutes. Drain, return the noodles to the pot, and toss with 2 tablespoons of the butter and 1 tablespoon of the parsley. Set aside and keep warm.
In an extra-large skillet, melt the remaining 2 tablespoons butter over medium-high heat. Add the chicken, season with the paprika and a good pinch of salt and pepper, and cook until browned and cooked through, 8 to 10 minutes. Use a slotted spoon to remove the chicken to a plate and set aside.
Add the mushrooms, onion, and thyme to the drippings in the skillet and cook over medium-high heat, stirring occasionally, until the onions have browned and the mushrooms have released their moisture, 5 to 6 minutes. Sprinkle in the flour and cook for a few minutes before whisking in the wine. Let the mixture boil and thicken, then slowly add the vegetable broth and soy sauce. Let cook until thickened, 2 to 3 minutes more.
Return the chicken to the skillet, along with any juices from the plate, and cook until heated through, about 1 minute. Remove from the heat and stir in the sour cream, mustard, chives, and 2 tablespoons of the parsley. Taste and adjust the seasoning.
Serve over the buttered noodles and garnish with the remaining parsley.