The acne is said to be largely from the rapidly changing test levels and shock your endocrine system is experiencing at that point post cycle... I would think the mood changes would be due to the same.
I'm not really sure you would attribute those sides to clomid or nolva really... my pocket drug refs I just checked doesn't even list acne as a side of either (but they are of couse talking of them alone... not with a cycle LOL).. I think my PDR lists acne as "very rare" for clomid and I don't remember seeing it at all for nolva. But then again, they're not talking about how clomid affects males because these aren't prescribed for males.
As I said though, it might just be, for the most part, the cycle AS levels dropping and your body's hormone levels in bigtime flux. I know bros who have used both, and got acne from both... and some who don't see acne from either... depends how prone you are I guess and prolly what your cycle is.