Do we have an exact date of death for Lord Nasher? I'm aware that he died during the Spellplague, and I remember reading somewhere an approximate date range for his death. However I can't find it, nor do I believe I've ever seen an exact date of death.
Also, I'm aware that he died without naming an heir. However what occurred after this death, were there any battles, or did any of them rule prior to the Mountain erupting?
No date was ever given for his death, however the kings of Neverwinter who came after him are explicitly referred to as his descendants.
It's never stated that Nasher had an heir, but one piece of lore did say he had an adopted uthgardt daughter and these descendants were probably her children.
When life turns it's back on you...sneak attack for extra damage.