I too have a hairy chest and can't get anything to stick beyond the nipple region. After lots of trial and error, I found three things that work:
1. For shorter runs (< 10 miles), I only have chafing problems when it's hot and I soak my shirt with sweat. In this case, I'm good to go after a swipe of bodyglide;
2. For longer runs: wipe the nipple with rubbing alcohol to remove the surface oils, let it dry, and stick on a little circular or square bandaid. Allow a few minutes for complete adherence before heading out for the run;
3. Using the same procedure as 2, nip guards. They work well, but are a bit expensive.