Preheat the oven to 300°F. Place rack on a lower level.
In a medium bowl, combine the butter, Worcestershire sauce, cayenne pepper, garlic powder and salt. Stir in the pecans and gently toss with the chili powder to coat. Spread the coated pecans on a baking sheet.
Bake for 30 minutes, stirring every 10 minutes. Let cool and store in a covered container.