Rinse and drain chard; pat dry with paper towels. Trim stalks from chard leaves, reserving stalks and leaves. Coarsely chop stalks to equal 1 cup; discard remaining stalks. Chop leaves.
Heat a large nonstick skillet over medium-high heat. Add pancetta to pan; sauté 2 minutes or until lightly browned, stirring frequently. Add garlic and chard stalks to pan; sauté 2 minutes or until tender, stirring frequently. Add half of chard leaves to pan; sauté 1 minute or until leaves wilt, stirring frequently. Add remaining chard leaves and pepper to pan; sauté 1 minute or until leaves wilt, stirring frequently. Sprinkle with cheese.