I think it is divided. Some believe that he is practical and resourceful. Koreans in general think "my country first" is a non-question. But trade wars in general are seen as foolish.
Let me guarantee you, if NK signs peace treaty with the US, South Koreans will absolutely support Donald Trump winning the Nobel peace prize. I would too.
Others also point at his unilateral abandonment of the Iran deal and are critical. I think many see Trump's domestic politics as his reason for pursuing peace in North Korea.