In heavy saucepan, over low heat, melt chocolate chips with EAGLE BRAND(R) and vanilla, stirring frequently.
Remove from heat. Add peanut butter chips; stir just to distribute chips throughout mixture.
Spread evenly into wax paper lined 8- or 9-inch square pan. Chill 2 hours or until firm. Turn fudge onto cutting board; peel off paper and cut into squares. Store leftovers covered in refrigerator.