Preheat oven to 350°F. Line a large baking pan with parchment paper. Set aside.
In a large bowl, combine the oats, walnuts, banana chips, cinnamon, salt, and nutmeg. Set aside.
In a medium bowl, combine the mashed banana, coconut oil, honey, and vanilla. Stir until well blended.
Add the wet mixture to the oats and mix until thoroughly combined. Spread oat mixture onto baking pan in an even layer.
Bake for 25-30 minutes, stirring halfway through, until granola is browned. Remove from oven and let cool completely on baking pan. Store in an airtight container at room temperature.
Notes
Granola will keep in an airtight container for up to three weeks.