Fry the bacon in a large nonstick skillet over medium high heat until crisp on both sides. Drain on paper towels. Assemble the sandwiches one at a time. Toast 2 waffles in a toaster according to package directions. When cool enough to handle, spread 2 tablespoons of Nutella on one waffle and 2 tablespoons peanut butter on the other. Sprinkle 1 teaspoon cinnamon sugar on the peanut butter covered waffle. Crumble one bacon slice over top, pressing lightly down into the peanut butter. Top with one half of banana slices and place the Nutella covered waffle on top, Nutella side down. Repeat to make the 3 remaining sandwiches. Serve immediately.