Well, it looks like the PDS slot in the computer probably works.
I have not recapped it. I will do it today. I tired with 2 different nubus video card that is working on iici and both are not working with adaptor. No bent pins or missing components. See attached pic if I missed anything.
Given you already tried Nubus cards that work in another computer, it is most likely that there is an issue with your riser card (although this can't be known with certainty unless you try it in another IIsi, or another riser in your IIsi).
You're going to have to do a lot of tedious manual stuff to troubleshoot it, or send it to someone like Amiga of Rochester or something.
If it was my board, I would photograph it or draw a sketch with every chip pin represented, and visually inspect where they start and finish and check continuity with a multi meter, before marking each one I've checked on the photo / drawing.