Preheat oven to 375 degrees.
In a large bowl, whisk together milk, chia seeds, mashed bananas, eggs, vanilla, and oil.
In a separate bowl, combine oats, cinnamon, baking powder, and salt.
Combine wet and dry ingredients and stir until mixed. Fold in 1 cup of the berries.
Pour mixture into a well-greased 8x8 baking dish and top with final ½ cup of berries.
Bake uncovered for 40-45 minutes, or until top is lightly golden and oats are "set".