Preheat your oven to 400°F.
In a large bowl, combine the sweet potato cubes, melted butter, olive oil, brown sugar, cinnamon, salt, black pepper, and nutmeg. Toss until the sweet potatoes are evenly coated.
Spread the sweet potato mixture in a single layer on a baking sheet lined with parchment paper.
Roast in the preheated oven for 25-30 minutes, stirring halfway through, until the sweet potatoes are tender and caramelized.
During the last 5 minutes of roasting, sprinkle the chopped pecans over the sweet potatoes to toast them slightly.
Remove from the oven and let cool for a few minutes before serving.