Spray 8 regular-size muffin cups with cooking spray; set aside.
In medium microwavable bowl, heat butter uncovered on High 20 to 30 seconds or until melted. Mix in marshmallows; microwave uncovered on High for 30-second intervals until marshmallows are melted and mixture is smooth when stirred. Add cereal; mix until fully combined. With greased hands, add about 1/4 cup cereal mixture to each muffin cup, and press gently to mold into a nest shape.
Unroll and remove paper from Betty Crocker Fruit Roll-Ups snack labeled Blazin' Blue/Green. Use small kitchen scissors to cut out from green portion of snack for strips of "grass," and place in the nests. Top with 3 "eggs," using Betty Crocker Fruit Gushers snacks of varying colors. Remove from muffin cups, and store covered up to 5 days.