Place a rack in the center of your oven and preheat the oven to 325 degrees F. Line an 8- or 9-inch square baking dish with parchment paper so that two sides of the paper overhang the sides like handles. Coat generously with nonstick spray.
Spread the oats, nuts, sunflower seeds, and coconut flakes on a rimmed, ungreased baking sheet. Toast in the oven until the coconut looks lightly golden and the nuts are toasted and fragrant, about 10 minutes, stirring once halfway through. Reduce the oven temperature to 300 degrees F.
Meanwhile, heat the honey and peanut butter together in a medium saucepan over medium heat. Stir until the mixture is smoothly combined. Remove from the heat. Stir in the vanilla, cinnamon, and salt.
As soon as the oat mixture is finished toasting, carefully transfer it to the pan with the peanut butter. With a rubber spatula, stir to combine. Let cool for 5 minutes, then add the chocolate chips (if you add the chocolate chips immediately, they will melt).
Scoop the batter into the prepared pan. With the back of a spatula, press the bars into a single layer (you also can place a sheet of plastic wrap against the surface to deter sticking, then use your fingers; discard the plastic prior to baking).
Bake the healthy granola bars for 15 to 20 minutes: 20 minutes will yield crunchier bars; at 15 they will be slightly chewier. With the bars still in the pan, press a knife down into the pan to cut into bars of your desired size (be sure to pick a knife that will not damage your pan—I typically cut into 2 rows of 5). Do not remove the bars. Let them cool completely in the pan.
Once the bars have cooled completely, use the parchment to lift them onto a cutting board. Use a sharp knife to cut the bars again in the same place, going over your lines to separate. Pull apart and enjoy!
TO STORE: Store granola bars in an airtight container at room temperature for up to 1 week or refrigerate for 2 weeks.
TO FREEZE: Wrap bars airtight and store them in a ziptop bag in the freezer. Let thaw in the refrigerator or at room temperature.