It's a trade that helps both teams, I think, which is a rarity.
Nash is a top-flight PG who can run an offense and make things easier for the guys around him. He's now got defenders around him, a frontcourt that will control the boards, and two wings who can get out on the break, one of whom is a consistent 3-point threat.
I might have done OK standing pat with Melo and then drafting the best available PG at this point, but I didn't feel as though I really wanted to do that.
I also now have 8 picks in the next 5 rounds (my final pick is the 10.17), so I've got some chips to play with.