that's freaking HOT!

Aside from the nipple sticker/band-aid thing, this is probably the best suggestion by far... at least for summer riding. I wouldn't want to wear a base layer if I didn't have to in the summer, but it would be ok for winter riding.

Has anybody ever tried using chamios cream on their nipples? I haven't, but I suppose it would work good for the chafing. Just don't use too much, or your friends might think you have some mamory problems.