Cover a large cookie sheet in foil and butter lightly. Fill pan with single layer of saltines. Cover completely breaking crackers to fit if necessary. Simmer butter and brown sugar for 5 minutes. Drizzle over crackers covering well. Bake in a 350 oven for 10 minutes. Remove from oven . Immediately pour on chocolate chips and spread over all while they are melting, to cover. Sprinkle with pecans and let cool. Break into pieces and store in an airtight container.