heat 1 tablespoon olive oil over medium-high heat in a large, wide saucepan. Add the pancetta turning it every so often to brown each side. approx. 10 minutes. Remove it from the pan using a slotted spoon to a paper towel then transfer to a bowl. Leave the heat on and the drippings in the pan and if needed add a tablespoon of olive oil. Add the onions, carrots, celery, Swiss chard and the red pepper flakes. Cook over medium heat until the vegetables are soft and beginning to brown, about 7-8 minutes. Add the garlic, cook for another minute more. Add the greens and cook until wilted. about 2-3 minutes. Season with salt and pepper to taste. Transfer to the pancetta bowl, set aside.