The process of creating a metamorphic rock is a chemical change because we are changing one rock into a whole new different type of rock.
Explanation:
Remember a chemical change is changing the core basis of what something is. Common example of a chemical change is burning wood, when you burn wood that wood turns into ash, which means it's no longer wood.
In this case metamorphic rocks are usually formed by intense heat and pressure, which converts the rock into a different type of rock.
To conclude, metamorphic rocks are formed by intense heat and pressure, which converts a rock into a different rock. "The process of creating a metamorphic rock is a chemical change because we are changing one rock into a whole new different type of rock."