Preheat the oven to 300 degrees (F). Prepare a large sheet pan by lining with parchment paper and set aside.
Add the almonds to a food processor and do a quick pulse (maybe only 3-4 times). Now add the remaining nuts: pecans, walnuts, pumpkin seeds, and sunflower seeds. Do a few more pulses in the food processor so that you have various sizes and textures of nuts and seeds.
Now add the coconut flakes and chia seeds to the mixture.
Prepare the syrup: in a small saucepan, place the coconut oil, pumpkin puree, maple syrup, coconut sugar, and vanilla extract inside. Heat to a medium heat and stir. Reduce heat to a simmer for 2-3 minutes, then remove from heat. Sprinkle in pumpkin pie spice and sea salt. The mixture should be thickened.
In a large bowl, combine the nuts/seeds mixture with the syrup. Toss to coat everything.
Spread out the mixture on a large baking sheet. Bake for 20 minutes, give it a quick stir, then bake another 15-20 minutes.
Remove from heat and let cool completely. Enjoy or place in a large air tight container.
*measured before melting the coconut oil while it's a solid.