- Be very patient in this match up. From what I've experienced/seen, 5B/5C can stuff Carl's 5B/5C at the right distance.
- Magnetism is very important in this matchup. When Carl is magnetized, it can turn the tide in your favour. If you do a 5D or a 2D when you hit Nirvana when activated, the active frames of attack will be longer and will pull Carl towards you which would most likely force Carl to block.
-IB is also very important. Look for any gaps (if any) when sandwiched between Carl and Nirvana to either 360, Backdash or sledge through.
Note: Not really 100% sure, but if Carl tries to do the Cantata "Unblockable" in the corner. You can prevent it by timing your meaty attack such as J.B when falling. If timed correctly, she should stop and get hit by your J.B. I am not sure if height plays a factor in it or not, but I've had a Carl attempt to do it on me and when I first discovered this I have been able to stay safe 70% of the time.
This is what I've got so far but if i know anything else i'll add some more.