Add the shallots and garlic to the same cast-iron skillet that you seared the chicken in. Lower the heat to medium-low. Sauté until they are fragrant, and the shallots are translucent.
Add the white wine to the pan. Make sure you are scraping up the brown bits off the pan - that is flavour! Let the wine reduce down by half, which should take between 3-5 minutes.