In a medium-sized pot, bring the milk and rice to a boil over medium heat. Remove from heat and allow to cool, uncovered, for about 10 minutes. (You can skip this step, but heating the mixture allows the rice to soften somewhat, creating a more pleasing texture once the pudding is refrigerated).

Add the remaining ingredients and stir well. Transfer to a large container with a lid. Allow to cool to room temperature, stirring 2-3 times to break up the chia and prevent clumping. Once cool, cover and refrigerate overnight. To serve, stir the chilled pudding and top with fresh berries, if desired.