If you decide to use spinach instead of kale or collard greens, take note that it cooks in much less time. Start by cooking the pasta, then cook the vegetables and sauce.
Cut along either side of the center rib of kale or collard greens from top to bottom; discard the ribs.
Make parallel cuts in one flat slice of pancetta. Turn the knife and slice across the cuts to form diced pieces.
Heat the oil, then add the diced pancetta. Cook until browned and crisp on the edges, tossing to keep the pieces from sticking.