Place candy corn in a microwave-safe bowl (not plastic) and heat in several 30-second intervals, stirring after each interval, until candy corn is warm, melted, and smooth.
Stir peanut butter into melted candy corn until thoroughly combined; transfer candy to the prepared pan, pressing and smoothing the candy into the corners of the pan.
Place chocolate chips and vegetable shortening into the top of a double boiler set over simmering water.
Heat the chocolate, stirring constantly, until just warm, melted, and smooth.
Spread warm chocolate over the peanut candy. Chill in refrigerator until candy is set, at least 30 minutes, before cutting into squares.
