Bear in mind kratom is an opiod (this is why it works well for SA). So you need to investigate whether opiods are going to be a problem with Nardil (fairly likely). Kratom also (possibly) does something with serotonin, so imo, I would avoid the combo.
Kratom isn't (contrary to what you might hear online) something to be take lightly imo. The comparisons to caffeine you see online are ridiculous. I have tried it myself numerous times, and its clearly an opiod. I no longer take it because I liked it a little bit too much.
Just my opinion though.