Heat a small pot over medium heat and add the coconut oil. Chop the apple and add it to the pan, stirring to coat. Let the apple sauté for 4-5 minutes. Add the oats and toast for another minute. Add a pinch of salt and the maple syrup then slowly add the milk one half cup at a time, allowing the mixture to come to a simmer and thicken between additions. Continue to stir and add the coconut and chia seeds. Bring the mixture to a simmer and add enough milk to reach your desired consistency. Separate into two bowls and top with walnuts (if using) and additional maple syrup.