Add olive oil to a large skillet and preheat over medium-high heat. Season chicken breasts with salt and pepper. Add chicken to skillet and saute until cooked through, about 10-12 minutes, turning once. Transfer to a plate and keep warm. Pour chicken broth into hot skillet. Whisk in the cream, mustard and tarragon or oregano. Cook and stir for about 2 minutes.
Pour sauce over chicken and serve.