Is there anything you can do when you have added to much thyme to a dish?

Well, of course Cher sang a whole song about it and I don't think she ever found a way to turn it back. ;-)

What hardlikearmour said, but also when I imagine a cacciatore with too much thyme, I think I might try throwing a Parmesan rind in there (if you have one), to add another strong flavor to help balance the dish. I would probably do that anyway for depth, but it might, along with HLA's suggestions, help a little.

I find that herbs are pretty volatile with cooking -- they tend to dissipate as they cook. If the chicken is done, but the sauce is too thymy pull the chicken out and continue to cook the sauce to see if the flavor lessens to an acceptable level. The other option is dilution -- add more tomato and broth.