Add the red onion to the pan and cook until translucent, 5 to 6 minutes. Add the vinegar, chicken broth, mustard, sugar, salt, and pepper to the pan and stir to combine. Add the bacon back to the pan along with the rice and cook, stirring occasionally, until the liquid is absorbed, 7 to 10 minutes. Stir in the dill. Allow to cool slightly before serving.