Corn syrup isn’t just used in pecan pie as a sweetener. It also creates a smooth texture in the filling by preventing sugar crystallization during baking. No one wants a grainy pie!
I’ve seen suggestions online for substituting corn syrup with maple syrup, honey, agave, brown rice syrup, golden syrup, molasses, and cane syrup, etc. All of these products contain sugar, and since pecan pie is never going to be a healthy food, I prefer to take the “everything in moderation” approach and just use the corn syrup since it is cheap and widely available.
It’s also important to note that corn syrup is not the same as high fructose corn syrup. And while some corn syrups contain HFCS, you can find many that don’t.