Preheat the oven to 350 degrees. On a large baking sheet, roast the pecans for 10 to 12 minutes. While the nuts are still hot, stir in 2 tablespoons butter. Turn the oven up to 375 degrees.
Sift together the flour, salt and baking soda or baking powder in a medium mixing bowl. Using an electric mixer, cream fat and sugar in a large bowl until light and fluffy. Add the corn syrup, if using. Add the liquid or egg and beat thoroughly. Beat in the vanilla. On low speed, gradually add the dry ingredients until thoroughly combined. Scrape down the sides once with a rubber spatula. Add the pecans and chocolate chips. Beat 5 seconds on low. Use the rubber spatula to finish mixing well.
Spray cookie sheets lightly with nonstick cooking spray. With a tablespoon or small ice cream/food scoop (I use a No. 40, about 11/2 inches diameter), drop slightly heaped tablespoons of batter about 2 inches apart onto the greased sheets. Bake the cookies for about 12 minutes or until the edges just begin to brown. Remove from the oven and let the cookies cool on the sheet on a cooling rack for 3 minutes, then remove the cookies to a rack to cool completely.
Variations: Replace the pecans with walnuts or replace semisweet chocolate chips with white chocolate and the pecans with macadamia nuts. For "supercookies," in addition to the pecans, add 1 cup roasted, chopped walnuts.