Heat olive oil in a large skillet over medium-high heat. Add pancetta and cook, stirring occasionally, for 4-5 minutes or until lightly browned. Remove from skillet and drain on a paper towel.
Add 2 tablespoons butter to same skillet. Once butter melts, add garlic and cook for 1 minute, stirring frequently and scraping the pancetta remnants from the bottom of the skillet. Add shallots and cook for 1-2 minutes.
Add green beans, lower heat to medium, cover with lid and cook for 8-10 minutes, stirring every few minutes. Add Marsala wine and additional tablespoon of butter, cooked pancetta and salt and pepper and cook for another 3 minutes or until beans are tender but not soft. Serve topped with toasted hazelnuts.