Process dates, almonds and almond butter in a food processor until nuts are coarsely ground and mixture is well combined. Lightly coat a 12-cup miniature muffin pan with cooking spray. Divide date mixture evenly among muffin cups, pressing into bottoms and up sides of cups to form mini piecrusts.
Set aside 12 blueberries. Cut 12 thin slices from nectarine. Place on a plate with reserved blueberries; cover and refrigerate.
Place remaining blueberries in a medium bowl; lightly mash with a potato masher or fork. Finely chop remaining nectarine to equal 2 tablespoons; add to mashed blueberries. Add yogurt and honey to mashed blueberry mixture; stir to combine. Divide mixture evenly among muffin cups. Freeze until firm, about 2 hours. (Pie bites may be frozen, covered, overnight.) Let stand at room temperature for 5 to 10 minutes before serving. Top each with 1 blueberry and 1 nectarine slice.