Preheat the oven to 325 degrees F. In a small bowl, mix together the salt, chili powder, cumin, allspice, cayenne, cinnamon, and paprika. In a large skillet over medium-high heat, add the butter. When the butter is melted, add the sugar and soy sauce. Stir to melt and then stir in the spices.
Add the pecans and toss to coat them in the spiced butter. Cook and toss until the butter is absorbed into the nuts, 2 to 3 minutes. Spread on a rimmed sheet pan and bake until the nuts are fragrant and toasted and the coating is caramelized, 15 minutes. Let cool slightly on the sheet pan and serve warm.