Add the chopped pecans to a medium saucepan and heat over medium heat. Toast the pecans for 2-3 minutes, stirring frequently so they don't burn.
Carefully pour the water and sugar in the saucepan and stir to combine. Bring the mixture to a simmer, and simmer for 10 minutes, stirring occasionally.
Remove from heat and strain out the pecans with a fine mesh strainer, reserving the liquid and discarding the pecans (or save them for ice cream topping).
Allow the syrup to cool at room temperature for 15 minutes, then transfer to a syrup bottle or mason jar and store in the fridge for up to 2 weeks!