In the sense that everything is chemicals, yes. But you typically wouldn't describe a butterfly growing a wing or a welder making a blue weld from metals that are normally very much not blue as "growing from chemicals". I guess you could argue about the butterfly, but I think few people would say that chemicals are involved in welding steel, despite iron, carbon and tungsten being chemical elements

Well, the counterargument is that in theory, you can imagine a way to create structural color regardless of substrate. So imagine a technology that shines a laser on a car or a block of concrete and makes it blue; I'd argue that's correctly "without chemicals".

Of course, I doubt you can do that to any random substrate, since the color will depend on the properties of the material.