Make the sauce
Stir the mustard seeds into the pan drippings and cook over medium-high heat, stirring, for about 15 seconds. Add the wine and broth and bring to a simmer. Reduce the heat to medium and cook, stirring, until slightly reduced, 1–2 minutes. Stir in the cream and mustard and cook for 1 minute to blend the flavors. Return the chicken and any juices from the plate to the pan and simmer over medium heat, about 1 minute. Season to taste with salt and pepper. Slice the chicken and serve drizzled with the sauce.