Hilde IMO is one of her worst matchups. Because Hilde can play at any range Mina does, and pretty much do it better than Mina. (at least in this matchup.) Oh and try any of your long range lows. You will get 6B+K'd on reaction by any decent Hilde with decent reflexes. Or if she was holding a B charge, you can enjoy getting punished almost no matter what range you were at. Except 2A+B. In which case you've probably alredy been 6B+K'd because even if you cancel the thing you can get hit by it on reaction.
When playing against Hilde with Mina I often resort to 9B+K series/throw mixups.
1) Because Hilde can't charge A that shit.
2) Because Hilde doesn't exactly have the greatest punishers for it if she guesses right.
Other moves to keep in mind would be 6B series once again for her generally weak punishers and inability to be charge A'd unless she by chance caught you while holding a B charge after blocking 6BB. In which case, keep doing 9B+K and B-throw MOAR so she stops that shit. And 22A, to stop her from abusing what might be the second best step in the entire game. Also, 4KB if she's trying to frame trap you. And against Hilde it's not bad by itself because of the weak punishers issue and the second hit tracking very well.