Spray an 8-x8-inch pan or a loaf pan with nonstick spray. Line the pan with parchment paper and spray again lightly with nonstick spray.
Melt the frosting by heating it in the microwave for about 30 seconds.
Put the chocolate chips in a microwave-safe bowl (or melt them in a saucepan over low heat). Microwave one minute, stir, then microwave in 30-second intervals until the chocolate chips are completely melted and smooth.
Add the melted frosting to the bowl and stir until completely combined. Scrape the fudge mixture into the prepared pan. Let sit at room temperature until firm, or refrigerate to speed up the process.
Cut the fudge into pieces. Store in a covered container, and eat within about 3 days. This fudge freezes well too.