In a mixing bowl, whisk together the chia seeds, almond milk, maple syrup (or agave), and vanilla extract until well combined.
Let the mixture rest for 5 minutes, then whisk again to break up any clumps and help the chia thicken evenly.
Cover and refrigerate until thick and pudding-like, at least 2 hours (best after about 4 hours or overnight).
While the pudding sets, blend the mango chunks with the mango puree until smooth. (If you like texture, reserve a few mango chunks to dice for topping.)
Once set, stir the chia pudding. Divide into serving jars or glasses, layering chia pudding and mango puree as desired. You can mix it up as well.
Top with optional shredded coconut, pumpkin seeds, and extra mango. Serve chilled. Store covered in the refrigerator for up to 3 days (up to 5 days if kept airtight and the mango kept separate).