Put cashews in a bowl. Pour enough water over cashews to cover completely; set aside for 2 hours to soak.
Drain and rinse cashews. Put cashews in a blender with 3 cups water, maple syrup, vanilla extract, and salt; blend until smooth. Add chia seeds and pulse blender until seeds are lightly integrated; transfer to a large bowl. Refrigerate 8 hours to overnight before serving.
