Combine the butter, evaporated milk, sugar, and salt in a medium saucepan.  Bring to a boil, over medium heat, stirring constantly.  Boil 4 to 5 minutes, continuing to stir,  Remove from the heat.  Stir in the marshmallows, choc chips, nuts and vanilla.  Mix vigorously for 1 minute or until the marshmallows are melted.  Pour into lightly greased pan or dish.  Chill until firm.  Eat!!!!!