Preheat the oven to 425 degrees F. Line a rimmed baking sheet with parchment paper.
Arrange the pancetta in a single layer on the prepared baking sheet. Bake until golden brown and crisp, 8 to 10 minutes. Transfer to a paper-towel-lined plate to drain.
Meanwhile, mash together the Gorgonzola, sour cream and lemon juice in a bowl. Add the milk and whisk to combine. Season with salt and pepper.
Arrange the iceberg wedges and tomatoes on 4 plates. Drizzle with the Gorgonzola dressing and crumble the pancetta over the top. Garnish with the chives.