Break the graham crackers into 4 as they are scored. Place close together on 2 average sized cookie sheets with 1/2 inch lip. Don't keep them intact like they come because the sauce needs to ooze between them but still put the crackers real close together on the sheet.
In saucepan, stirring constantly, heat to boiling the butter and the sugar on medium to low heat. Boil 2 minutes.
Pour evenly over graham crackers. Using spatula, lightly smooth the sauce. Sprinkle with chopped nuts. Bake 10 minutes.