Cream together the butter, vanilla, salt and peanut butter. Stir in 2 cups of the confectioners' sugar, nuts and all but 1/2 cup of the graham cracker crumbs. Add the last 1/2 cup of graham cracker crumbs only if needed; otherwise it may be difficult to mold the balls.
Form the mixture by hand into 1 inch balls. Roll each ball in the remaining cup of confectioners' sugar. Set the balls in a single layer on a cookie sheet and refrigerate until firm. At this point the cookies may be dipped in melted chocolate or they can be left plain. Store in an airtight container in the refrigerator.
To Dip Balls In Chocolate: In the top half of a double boiler; melt the chocolate chips and shortening just until the chips are melted. Remove from heat but leave over hot water. Insert a toothpick into the chilled balls and dip into the melted chocolate until coated. Set on waxed paper until hardened.