Combine Dry Ingredients. In a medium bowl or a jar, combine oats, chia seeds, cinnamon, nutmeg, and salt. Stir to combine.
Add Wet Ingredients & Mix-Ins. Next, mix in pumpkin puree, maple syrup, and vanilla. Add 1 Tbsp. pecans or pumpkin seeds. Pour in milk and stir to combine until no clumps remain.
Taste & Adjust. Taste and add additional syrup, spices, or vanilla, as desired.
Cover and refrigerate at least 20-30 minutes, up to overnight to let the liquid soak into the oats.
Serve & Store. Stir oats and top with additional pecans/pumpkin seeds, as desired. Enjoy! (Oats will keep 2-3 days in the refrigerator.)