In theory, you should repot it in organic soil with no fertilizers or other additives. You'd do that by taking it out of the pot and washing down the roots to remove as much of the existing soil as possible, washing the pot and returning the plant to it with the cool clean soil.
This is because virtually any potted plant you buy is in soil that has fertilizer and possibly even pesticides in it. Some chameleons will eat the soil from the plants. If it's full of toxins, that's not a good thing.
Many people suggest covering the top soil with fairly good size rocks (too big for your chameleon to swallow) to prevent it from eating the soil.