Line tray with parchment paper or wax paper.
Wash apples; dry thoroughly and insert wooden stick into stem end of each apple; place on prepared tray.
Place chocolate chips, 2/3 cup peanut butter chips and 1/4 cup shortening in medium microwave-safe bowl.
Microwave at MEDIUM (50%) 1 minute; stir.
If necessary, microwave at MEDIUM an additional 30 seconds at a time, stirring after each heating, just until chips are melted when stirred.
Dip bottom three-fourths of each apple into mixture. Twirl and gently shake to remove excess; return to prepared tray.
Place remaining 1 cup peanut butter chips and remaining 2 tablespoons shortening in small microwave-safe bowl.
Microwave at MEDIUM 30 seconds; stir.
If necessary, microwave at MEDIUM an additional 15 seconds at a time, stirring after each heating, just until chips are melted when stirred.
Spoon over top section of each apple, allowing to drip down sides. Refrigerate until ready to serve.