Add the rolled oats, vanilla protein powder, almond milk, vanilla extract, chia seeds, maple syrup, pistachio butter, chopped pistachios, and salt to a mason jar or airtight container.
Stir thoroughly until all ingredients are fully combined.
Seal the container and place it in the refrigerator for at least 4 hours or overnight.
In the morning, stir the Pistachio Overnight Oats well.
If the mixture is too thick, add a splash of milk and stir until you reach your desired consistency.
Top with extra chopped pistachios, a drizzle of pistachio butter, or your favorite toppings.
Serve chilled and enjoy.