In a medium bowl, add banana and chia seeds. Mash with a fork until well combined. Add milk and vanilla extract; whisk until well mixed and no lumps appear.
Pour half into a glass container and cover. Add maple syrup and cacao powder to remaining half and whisk well. Pour into another container with a lid. Refrigerate both for at least 4 hours or overnight.
To serve: in 3 bowls or glasses layer equally both chia puddings with mix-ins.
Notes
Store: Refrigerate assembled and covered for up to 5 days.
Use cocoa powder in place of cacao powder. Both produce a rich chocolaty flavor, but cacao is processed at a lower temperature, retaining a bit more nutrients.
If it's too thick by the time you serve it, thin it out with a little splash of milk.