It appears a bit iffy. Here's a quote from post asking about compatibililty with the 18-200 and the 80-400:
None of the current Nikon teleconverters will work with either of these lenses. The Kenko Teleplus Pro 300 series of teleconverters will work with the 80-400mm VR. The situation with the 18-200mm is a bit iffy -- at 18mm the clearances are quite close, so the teleconverters should be used with caution if at all. Kenko specifically states that it does not recommend using their TC's for lenses that have a zoom range that starts at under 50 mm.
You can find more in the Filters and Accessories section under Mastering your Nikon Lenses.