Pour the mango nectar, greek yogurt, and protein powder into a blender, then blend until very smooth.
Add the liquid to the silicone popsicle mold, then insert the sticks. Let the popsicle liquid set overnight.
Notes
Let it Set: As I mentioned before, you need to give the popsicles time to rest. The liquid mixture will freeze really well if left alone (aka don't keep checking!!) and if it is given the time to sit overnight. Trust me, I've tried a few times to do just 2-3 hours and it just wasn't enough time.