In a saucepan, melt the butter and brown sugar over medium to medium high heat. As soon as the toffee begins to bubble, set a timer and cook for 7 minutes. STIR constantly. NOTE: When toffee starts boiling, depending on your cooktop, you may need to turn the heat down to medium. Remove from heat and immediately drizzle the hot toffee mixture over the pecans. Quickly spread in an even layer over the pecans. Sprinkle chocolate chips over hot toffee and cover with a baking sheet or large flat pan. Wait 2 minutes, remove the pan, and smooth out the melted chocolate chips with a spatula. Right away, sprinkle on the remaining 1/4 cup chopped pecans. Cool until chocolate sets, break apart, and enjoy! (You could cool faster in the refrigerator, just be sure NOT to store in the refrigerator. Only chill long enough for the chocolate to set.) Enjoy!