3 tablespoons olive oil
2 tablespoons Dijon mustard
1 tablespoon light brown sugar
2 teaspoons chili powder
2 garlic cloves, finely chopped
One 3 1/2-pound whole chicken, rinsed and patted dry
Salt and freshly ground black pepper
One 14.9-ounce can beer
Sweet and Spicy Pickled Vidalia Onions (see below), for serving

Sweet and Spicy Pickled Vidalia Onions:
1 large Vidalia onion, thinly sliced crosswise
1 tablespoon apple cider vinegar
1 teaspoon kosher salt
Pinch of cayenne pepper
Pinch of sugar