In a large microwaveable bowl, combine milk, marshmallows, chocolate chips, sugar and salt.

Bring to a boil in microwave. Stir well and cook an additional 2 minutes in microwave.

Remove bowl from microwave. Add butter, vanilla, and chopped nuts and mix well.

Add crumbled Thin Mint Cookies to mixture. 

Pack the mixture into a 9 in square pan. Refrigerate to harden. 

Cut into squares.