During the song, "My Lullaby", Nuka sings "Now you've found yourself somebody to chase Simba up a tree" and she responds with "Well the battle may be bloody, but that kind of works for me."
Now fast forward to the scene where Simba is ambushed by Zira's pride and he tries to escape by climbing a huge pile of logs. Nuka chases him up the "trees" (technically a log pile) until they come crashing down on him, killing him in the process.