In your blender add the almond milk, peaches, coconut butter, vanilla, cinnamon, and sweetener (if using).
Blend on high, until completely smooth
Pour half the mix into a quart-size jar, add the chia seeds, and shake well. (Make sure none of the seeds have stuck to the sides or bottom of the jar)
Add the other half of the blended peach mix, tighten the lid, and shake until the seeds have distributed evenly
Put the jar into the fridge and allow to chill for 4 hours, or overnight.
You'll know it's done when the smoothie has thickened and is thoroughly chilled