Anything that would be improved by paint is on the table at a thought.
Likely way to powerful in a combat sense. You could tag enemy combatiants on a battlefield in dayglo orange or turn the whole landscape into that zebra ship paint they used in ww2. Hell, just turn everything bright white during the day and black at night. Would be a nightmare.
Even if you limit it by range, like only recolouring things within 1 meter of where you touch… It’d still be a great power! Imagine the money you’d make, flawlessly painting whole rooms in seconds.