Hi mamachan! Welcome to MDC!
First, my daughter nurses to sleep, too, and often takes "naked naps". She always seems to stay dry, though I don't know how or why that works. We started doing it a long time ago; the first time I put a towel under her or something and expected an accident, but it didn't happen. Never had an accident (yet!), after many many naked naps. Just putting that out there in terms of nursing to sleep.
Second, my dd has been pretty much ready for potty training for a while -- has been reliably peeing and pooping in the potty if naked for several months now -- but I have been focusing on night weaning first. One thing I noticed just recently is that while she used to be fine about pooping on the potty while naked (yes, this gal is naked fairly often
) she recently told me she was "scared". I asked her why, and it came out that the potty seat is cold and uncomfortable in this cold weather. When possible, I try to warm it up, (washing with a warm washcloth, then drying), but of course there isn't always time. So I've just upped the praise a notch (I always praise her, but since it had become such an everyday occurrence, it was more like "yay!" rather than "WOW you amazing little girl look at that! I'm so proud of you!!" et al.