Steps

1. Preheat oven to 400°F. Place the pecans and oats on a baking sheet in an even layer. Bake 6 minutes, stirring halfway through, until the oats are light brown and the pecans are aromatic. Set aside to cool.
2. Lightly coat a very large bowl with cooking spray oil and add the popcorn to it.
3. Combine maple syrup, butter and salt in a small saucepan. Bring to a boil over medium-high heat and cook, without stirring, until a candy thermometer registers 297°F, about 7 minutes.
4. Working quickly and carefully, drizzle the maple mixture over the popcorn and then sprinkle the oat-pecan mixture evenly over the top. Carefully toss until well combined with a heatproof spatula or wooden spoon coated with cooking spray oil.
5. Let cool completely. Break into bite-sized pieces and store in an airtight container.

Notes

Never walk away from a cooking sugar syrup because it can increase in temperature very quickly and burn in seconds.