Melt the butter in a medium skillet over medium-low heat. Add the pecans and cook, stirring occasionally for 1-2 minutes, or until the pecans are shiny. Then add the maple syrup and cook, stirring frequently, until the syrup is absorbed into the nuts, another 2-3 minutes.
If you want these pecans as a snack rather than a salad topping, skip the chopping step and leave them whole.
You can use unsalted butter instead of the salted butter. Just a add a pinch or two of kosher salt in when you are melting the butter.
For a thicker coating, add one more tablespoon of maple syrup (for 3 tbsp total). The nuts will be a little sticky and have a more intense maple flavor.