Heat oven to 350°F (325°F for dark or nonstick pans). Place paper baking cup in each of 24 regular-size muffin cups.
Make cake batter as directed on box. Divide batter evenly among muffin cups (about two-thirds full). Bake as directed on box for cupcakes. Cool in pans 10 minutes; remove from pans to cooling rack. Cool completely, about 30 minutes.
Using melon baller, scoop out center of each cupcake, about 1 inch deep. Fill each with 1 heaping teaspoonful candies.
Spoon frosting into medium bowl; stir in enough food color until desired green color. Frost cupcakes with frosting; sprinkle with colored sugar. Top with yellow PEEPS® chick. Store loosely covered.