In a large mixing bowl, whisk together the flour, sugar, salt, and instant yeast until well combined.
Add the warm water and maple syrup to the dry ingredients. Stir with a wooden spoon or spatula until a shaggy dough forms and all the flour is hydrated.
Fold in the chopped toasted pecans until evenly distributed throughout the dough.
Cover the bowl tightly with plastic wrap or a clean kitchen towel and let the dough rise at room temperature for 12 to 16 hours, until it is bubbly and has doubled in size.
After the dough has risen, generously flour a clean work surface and your hands. Turn the dough out onto the surface and gently fold it over on itself once or twice to shape it into a rough ball. Do not knead.
Place the dough seam-side down on a large piece of parchment paper. Cover with a kitchen towel and let it rest for 30 minutes.
About 30 minutes before baking, place a Dutch oven with its lid inside your oven and preheat to 450°F (230°C).
Carefully remove the hot Dutch oven from the oven. Using the parchment paper, lift the dough and place it into the Dutch oven.
Cover with the lid and bake for 30 minutes.
Remove the lid and bake for an additional 15 minutes, until the bread is deep golden brown and crusty.
Remove the bread from the Dutch oven and transfer to a wire rack to cool completely before slicing.