Hello and welcome to BW forums
The shorter naps could be that she hasn't learned yet to transition from one sleep cycle to the next. It's great she can fall to sleep at the beginning of her nap alone, but perhaps she doesn't know what to do when she wakes. You could try a W2S method, here's a link:
https://babywhispererforums.com/index.php?topic=223809.0see naps option 1
use your usual soothing method such as shush/pat or a firm hand on her to help her stay asleep, she will still stir and wake but hopefully she will get the idea that she is to go back to sleep if you can help her with this. This method works in cycles, do 3-4 days then have a day off to see what happens. if she doesn't transition alone then go another round of W2S for 3-4 days again.
Another reason for waking after one sleep cycle can be UT 9under tired) meaning needing a touch more A time but your A time is good for age so I wouldn't go straight to this yet.
A times are guidance only and are changed to suit each individual LO so if you try W2S for 3-4 days and aren't having any change you could add on another 5-10 mins A and see if it helps.
I'm wondering when she wakes up from her catnap at 8 pm or 8:30, should I try to nurse her and put her right back down for the night
You will probably find the E times change as her naps lengthen and that this evening/BT thing changes too. But yes you can try just feeding and putting straight down again.
To be honest if she is waking in the morning at 8/8.30 I wouldn't expect BT to be before 8/8.30pm and lots of LOs wont' sleep a 12hr night so in those cases BT would be even later based on your morning WU time. So perhaps 9/9.30/10pm My DS only slept 10.5hrs over night.
You could also try a cluster, so rather than right before BT/S try an extra feed an hour or 30 min before and just see if she'll take a top up. My DS wouldn't feed to sleep and wasn't interested in feeds out of his routine times but he would take a BT feed no matter how close the previous E had been - so if he had a CN and ate after that he would eat again at BT (and even more than all the other feeds) as though he knew this was his big feed before night. I'd probably just keep offering the BT feed even if she refuses as one day she might change her mind.
Despite BT being late you're getting great nights with a good long stretch there, which is classed as sleeping through the night