Line an 8-in. square dish with foil; grease foil with 1 teaspoon butter and set aside.
In a large bowl, combine the corn syrup, peanut butter, vanilla, salt and remaining butter. Beat on high speed for 1 minute. Gradually add confectioner's sugar and mix well. Press into prepared pan.
In a large microwave-safe bowl, melt caramels with water; stir until smooth. Stir in peanuts. Pour over corn syrup mixture. Refrigerate for 1-1/2 hours or until firm.
Using foil, lift candy out of pan. Invert onto a cutting board; cut into 1-in. pieces. In a microwave, melt chocolate chips; stir until smooth. Dip candy in chocolate, allowing excess to drip off. Place on waxed paper; let stand until set. Store in the refrigerator.