Place 1 cup plain fat-free Greek yogurt in a blender. Add 1 cup passion fruit nectar, 1 cup guava nectar, and 2/3 cup fresh orange juice; process until smooth. Add 1 cup crushed ice; process until smooth. Pour into glasses. Serve immediately.
Smoothie Tip Choose ripe, in-season fruits and vegetables for the best-tasting beverage. If you prefer superthick fruit smoothies, freeze the fruit before blending.