Preheat the oven to 375 degrees F (190 degrees C). Coat a large casserole dish with cooking spray or mist with olive oil.

Combine salt, paprika, and pepper, and sprinkle over chicken cubes.

Melt 2 tablespoons butter in a large skillet over medium-low heat. Add the chicken and lightly brown on all sides, about 4 minutes. Transfer to the casserole dish. Remove artichoke hearts from the marinade and place among the chicken cubes. Reserve 1 tablespoon of the marinade for later.

Melt remaining butter in the same skillet over medium heat. Add mushrooms and stir until lightly browned, about 3 minutes. Combine flour and thyme; stir into the mushrooms. Mix chicken broth, sherry, and Dijon mustard together. Gradually add to the skillet, stirring constantly until lightly thickened. Taste and season with salt and pepper if needed.

Pour the sauce over the chicken and artichokes. Drizzle with the reserved artichoke marinade. Cover.

Bake in the preheated oven until chicken is no longer pink in the center, 15 to 18 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C). Garnish with chopped parsley.