Ya Op 48 #1 has a lot of qualities you'd see in the Ballades... it's pretty massive as far as the Nocturnes go... but I think Op.9 #3 is deadlier

If you play a bit of Liszt, Op 48 #1 will come a little easier... but 9/3, when it picks up... the left hand really exerts itself... it also has the fast/glittery passages that there are none of in the C minor nocturne.
Op.9 #2 is an excellent choice though. Memorable melody, a good piece for harmonic analysis, not too long, and is a good introduction into his writing style that you see in the other nocturnes.