Would the opteka 0.20x fisheye worn with my AF nikkor 35-75mm lens?

Would it work?

Yes, if you don't mind 30% of your photo(s) being blurred. I did a little quick research on this lens.
$40 for a fish eye lens? Are you serious?! Cheapest " real " fish eye I've seen was around $300.
The Opteka is a little on the heavy side, and could add extra stress to your Nikkor lens.
I'd pass if I were you.

It'll work, but expect fun over quality. It's worth remembering that your lens isn't that wide to begin with, the effect would be less pronounced than on the kit lens.

I did a search on flickr: .20&m=text Hopefully the link works. Have a look through a few of those images and see how you feel.

A cheap(ish) option that might provide better quality would be an older manual fisheye with a lens mount adapter. For instance: http://www.ebay.co.uk/...0915625982

You might find other makes of add-on lenses offer a better quality, people seem to like Raynox stuff for instance.

It will "work" as in function, but you're not going to get particularly useable shots out of it.