If you know he's a good reg you must have some stats on him. Feel free to post them.

I think the overbet ott polarizes villain's range a lot. If, as you said, he's a good reg, from utg he could open with monsters as well as some sc, and on that board you are way behind, loosing vs full houses (any AK, AQ, QQ, sometimes also KK), simply a better ace like AJ, straights (JdTd or other JxTx with one diamond played aggressively). He can also play in this way something like QhJh if he is aggressive, buy without any info is difficult to estimate a proper range. Also, you call otf, representing an ace, a queen and sometimes a fd or a combodraw, and I think his overbet ott most of the time could be to get value from random trips or draws. I think folding here is not so bad, almost always you are ahead only vs bluffs