He died in lion king 1, because Simba pushed him off the cliff. The hyena's surrounded their fallen leader, because they were so hungry and Scar announced them as they enemy, they ate him.
It is implied that Nuka could be Scar's son as he remarks "Kovu, Kovu, Kovu. Scar wasn't even his father", but it was never officially said in the film nor did The Lion King II filmmakers confirmed...
In the sequel, Jim Cummings did Scar's voice in Simba's nightmare scene. Jeremy Irons, the original voice for Scar, was either too busy on another film or was simply not asked to reprise his role.
Officially and canonically, no. However, it is implied that Nuka and Vitani could be Scar's cubs, but it wasn't made official by the Lion King II filmmakers. In the beginning of the film, Nuka...