Preheat the oven to 350 degrees F. Spread the pecans on a small baking sheet and bake until brown and toasty-smelling, about 10 minutes.
Meanwhile, put the bacon in a medium skillet over medium heat and cook, turning once, until crisp, 4 to 5 minutes per side. Transfer to a paper-towel-lined plate. Put 1 teaspoon of the bacon drippings in a medium bowl. When the bacon is cool, crumble and set aside.
Whisk together the bacon drippings, olive oil, vinegar, maple syrup, mustard and salt and pepper.
Toss the greens with the goat cheese, pecans and bacon in a large serving bowl. Drizzle with the dressing, toss to coat, season with more pepper and serve.