Preheat oven to 375°F.
Place a large, heavy pot over high heat with 2 tablespoons EVOO, 2 turns of the pan. Add the pancetta and cook until brown and crispy, 3-5 minutes. Remove pancetta with a slotted spoon to a paper towel-lined plate and reserve.
Add ground chicken to the pot with the pancetta drippings and cook until lightly browned, about 5 minutes, breaking it up into pieces with a wooden spoon.
Add the onions, carrots, grated garlic and bay leaf to the pot and cook until browned, about 8 minutes more. Season with salt and freshly ground pepper, then stir in the balsamic vinegar, scraping up the brown bits on the bottom of the pot.