Take a big mixing bowl and add rolled oats, chia seeds, chopped almond and chopped walnut. Mix it together. Pour the oil first and then, using a measuring cup, pour the maple syrup (the oil will grease the cup and the sticky maple syrup will flow off easily).
Mix everything and layer it on a big cookie sheet. Bake it for 40 minutes in the middle rack, tossing every 15 minutes, for even coloring and roasting. If you are making a big portion, you could do it in batches.
Once done, let it cool down completely before you add the dried fruits and other toppings.