Looking for something to thicken a sauce without messing up the flavor

I have a recipe that I love to make, Buffalo Chicken Pizza. It's as simple as it sounds; pizza made with chicken (in my case soy chicken) and mozzarella, but I replace the pizza sauce with buffalo sauce.

It's delicious but I'm always frustrated by how runny the sauce is, forcing me to eat it with a knife and fork. Is there something I could add to the buffalo sauce that would make it the consistency of pizza sauce without messing up the flavor?